In this review,we propose a comprehensive overview of additive manufacturing(AM)technologies and design possibilities in manufacturing metamaterials for various applications in the biomedical field,of which many are i...In this review,we propose a comprehensive overview of additive manufacturing(AM)technologies and design possibilities in manufacturing metamaterials for various applications in the biomedical field,of which many are inspired by nature itself.It describes how new AM technologies(e.g.continuous liquid interface production and multiphoton polymerization,etc)and recent developments in more mature AM technologies(e.g.powder bed fusion,stereolithography,and extrusion-based bioprinting(EBB),etc)lead to more precise,efficient,and personalized biomedical components.EBB is a revolutionary topic creating intricate models with remarkable mechanical compatibility of metamaterials,for instance,stress elimination for tissue engineering and regenerative medicine,negative or zero Poisson’s ratio.By exploiting the designs of porous structures(e.g.truss,triply periodic minimal surface,plant/animal-inspired,and functionally graded lattices,etc),AM-made bioactive bone implants,artificial tissues,and organs are made for tissue replacement.The material palette of the AM metamaterials has high diversity nowadays,ranging from alloys and metals(e.g.cobalt-chromium alloys and titanium,etc)to polymers(e.g.biodegradable polycaprolactone and polymethyl methacrylate,etc),which could be even integrated within bioactive ceramics.These advancements are driving the progress of the biomedical field,improving human health and quality of life.展开更多
Grease is extensively used in rolling bearings due to its inherent sealing properties.However,mechanical degradation typically occurs,resulting in a significantly shorter lifespan for the grease compared to the bearin...Grease is extensively used in rolling bearings due to its inherent sealing properties.However,mechanical degradation typically occurs,resulting in a significantly shorter lifespan for the grease compared to the bearing.Investigating aging mechanisms is essential.This study utilized rolling bearings to obtain mechanically aged greases.The aged samples were then subjected to do rheological test,FTIR test and friction test to examine the effects of aging time,radial load,and rotational speed.An innovative disk-ball-disk device was developed to study the friction characteristics of aged grease in rolling bearings.Additionally,a grease lubrication and friction model were proposed to further evaluate the lubrication performance of aged grease,using measured rheological parameters and the kinematic velocities of the disk-ball-disk device as inputs.The calculated friction coefficients matched well with disk-ball-disk experimental results.FTIR analysis revealed that the non-soap thickener’s structure remained stable,but additives depleted at high speeds.The structure of lithium soap thickener decomposed severely,leading to oil bleeding and a shortened replenishment duration.Over aging time,both greases had lower friction and viscosity due to gradual thickener breakdown,releasing bled oil and extending replenishment.Radial load minimally affected the properties of aged grease.This study may provide valuable insights into the aging mechanisms of grease and the enhancement of rolling bearing lubrication.展开更多
A novel temperature-preserved core chamber designed for depths exceeding 5000 m has been developed to enhance the scientific understanding of deep oil and gas reservoirs.This temperature-preserved core chamber employs...A novel temperature-preserved core chamber designed for depths exceeding 5000 m has been developed to enhance the scientific understanding of deep oil and gas reservoirs.This temperature-preserved core chamber employs an innovative vacuum layer for temperature preservation and is compatible with a temperature-pressure preserved coring system.The design principles and key parameters of the temperature-preserved core chamber were determined through static analysis.Numerical simulations assessed the mechanical properties of 70,85,and 100 MPa core chambers under conditions of 120-150℃.The results demonstrate that the temperature-preserved core chambers withstand the applied stresses without plastic deformation,and the vacuum layer maintains its integrity under these conditions.A 70 MPa class core chamber prototype was manufactured,and system integration tests were performed on a self-developed in-situ coring platform.The system demonstrated stable operation at 70 MPa for 120 min,with pressure fluctuations within 5%.Additionally,the integrated system operated without interference,enabling the successful extraction of cores with a 50 mm diameter.These findings provide valuable theoretical guidance and design recommendations for advancing oil and gas in-situ temperature-pressure preserved coring technologies in high-temperature and high-pressure environments.展开更多
The specific surface area(S S)and pore size(D)exhibit an inherent trade-off in the microscale design of bone implants:larger pores typically correlate with reduced surface area and vice versa.This relationship has att...The specific surface area(S S)and pore size(D)exhibit an inherent trade-off in the microscale design of bone implants:larger pores typically correlate with reduced surface area and vice versa.This relationship has attracted notable attention because of its critical role in the regulation of cell adhesion and osteogenesis.However,it remains largely unclear how S S and D affect the generated bone tissue and dynamically change during long-term osteogenesis.Herein,by applying rigorous geometric mapping to minimal surfaces,we constructed precisely partitioned and layer-by-layer thickened tissue models to simulate osteogenesis across different temporal scales and thereby track the dynamic evolution of geometric characteristics,permeability,and mechanobiological tissue differentiation.The high-S S samples were found to facilitate the rapid formation of new bone tissue in the early stages.However,their smaller pores tended to cause occlusions,hindering further tissue development.In contrast,low-S S samples showed slower bone regeneration,but their larger pores provided adequate physical space for tissue regeneration and mass transport,ultimately promoting bone formation in the long term.Mechanobiological regulation suggests that fibrous tissue formation inhibits additional bone formation,establishing a dynamic equilibrium between osteogenesis and pore space to sustain nutrient/waste exchange throughout the regenerative process.Overall,smaller pores are preferable in implants for minimally loaded osteoplasty procedures focused on early-stage bone consolidation,whereas larger pores are preferable in dynamically loaded implants requiring prolonged mechanical stability.展开更多
Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its commercialization.These challenges in...Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its commercialization.These challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode side.Since the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned issues.In this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and summarized.Crucially,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in detail.Finally,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.展开更多
This work systematically studied the effect of volumetric energy density E on the densification,mi-crostructures,tensile mechanical properties,and shape memory performance of a Fe-Mn-Si-Cr-Ni shape memory alloy(SMA)fa...This work systematically studied the effect of volumetric energy density E on the densification,mi-crostructures,tensile mechanical properties,and shape memory performance of a Fe-Mn-Si-Cr-Ni shape memory alloy(SMA)fabricated by laser powder bed fusion(L-PBF).An E of 90-265 J/mm3 is suggested to fabricate the Fe-Mn-Si-Cr-Ni SMA with minor metallurgical defects and a high relative density of above 99%.The increase in E can promote the formation of the primaryγaustenite and the solid phase trans-formation from the primaryδferrite to theγaustenite,which helps to achieve a nearly complete y austenitic microstructure.The increase in E also contributes to fabricating the Fe-Mn-Si-Cr-Ni SMA with superior comprehensive mechanical properties and shape memory performance by L-PBF.The Fe-Mn-Si-Cr-Ni SMA with a combination of good ductility of around 30%,high yield strength of above 480 MPa,an ultrahigh ultimate tensile strength of above 1 GPa,and large recovery strain of about 6%was manu-factured by L-PBF under a high E of 222-250 J/mm^(3).The good shape memory effect,excellent compre-hensive mechanical properties,and low cost of Fe-Mn-Si-Cr-Ni SMAs,as well as the outstanding ability to fabricate complex structures of L-PBF technology,provide a solid foundation for the design and fabri-cation of novel intelligent structures.展开更多
To enhance the adhesion of ceramic coatings in turbine blade Thermal Barrier Coatings(TBCs)systems,Laser Surface Texturing(LST)was employed to create microstructures on the metal bond coat.The bonding conditions and f...To enhance the adhesion of ceramic coatings in turbine blade Thermal Barrier Coatings(TBCs)systems,Laser Surface Texturing(LST)was employed to create microstructures on the metal bond coat.The bonding conditions and failure mechanisms of the ceramic coatings within these microstructures were thoroughly investigated.Femtosecond laser technology was used to fabricate three types of high-quality microstructure grooves:linear,sine wave,and grid patterns.These grooves exhibit uniform morphology,well-defined edges,and smooth inner walls.After ceramic coating deposition,columnar crystal structures grew perpendicularly along the groove walls,completely filling the microstructures and forming an arched support structure that significantly enhances mechanical interlocking and adhesion.Among the different microstructures,grid patterns demonstrated the best adhesion performance.In scratch tests,grid-patterned microstructures exhibited only localized small block spalling under high load conditions,avoiding large-scale delamination.This superior performance is attributed to the ability of grid pattern to effectively distribute stress in multiple directions and prevent crack propagation.By reducing stress concentration and enhancing mechanical interlocking points,grid-patterned microstructures also showed excellent resistance to spallation during thermal cycling,markedly improving the thermal resistance and adhesion of coating.展开更多
Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors c...Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static stimuli.Here,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic stimuli.Specifically,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential differences.The controllable and reversible polarization process of the conjugated polymers is fully in situ characterized.Then,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference outputs.Compared with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nW),as well as superior bio-friendliness.As demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning algorithms.This tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.展开更多
This review systematically summarizes recent advancements in the design of antibacterial hydrogels and the surface-related factors influencing microbial adhesion to polymeric materials.Hydrogels,characterized by their...This review systematically summarizes recent advancements in the design of antibacterial hydrogels and the surface-related factors influencing microbial adhesion to polymeric materials.Hydrogels,characterized by their three-dimensional porous architecture and ultra-high water content,serve as ideal platforms for incorporating antibacterial agents(e.g.,metal ions,natural polymers)through physical/chemical interactions,enabling sustained release and enhanced antibacterial efficacy.For traditional polymers,surface properties(e.g.,roughness,charge,superhydrophobicity,free energy,nanoforce gradients)play critical roles in microbial adhesion.Modifying the surface properties of polymers through surface treatment can regulate antibacterial performance.In particular,by referencing the micro/nanostructures found on natural surfaces such as lotus leaves and cicada wings,antibacterial surfaces with multiple superior functions can be fabricated.Collectively,these findings provide a theoretical basis for the rational design of multifunctional antibacterial materials,offering material-based solutions to address complex infection scenarios and advance infection management strategies.展开更多
Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity up...Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further application.Herein,from a new perspective,a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth(CC/Ni),which endows the supported active materials with exceptional electronic conductivity and structural stability.In addition,the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components,ensuring the structural integrity of electrodes upon cycling.More importantly,the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical reactions.Therefore,taking Ni_(3)S_(2)nanosheet(Ni_(3)S_(2)NS)anode as an example,the prepared Ni_(3)S_(2)NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm^(2)at 1mA/cm^(2)and high capacity retention of 1.68 mAh/cm^(2)at a high rate of 8mA/cm^(2).This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.展开更多
The effect of electro-pulsing treatment(EPT)with different peak current densities(Jm)on tensile properties of selective laser melting(SLM)-produced TC4 alloy was investigated for significant improvement in the tensile...The effect of electro-pulsing treatment(EPT)with different peak current densities(Jm)on tensile properties of selective laser melting(SLM)-produced TC4 alloy was investigated for significant improvement in the tensile properties of the alloy.When Jm is 30 A/mm2,the elongation is improved distinctly by 19.72%while the ultimate tensile strength remains nearly constant.The improved ductility is evidenced by deeper dimples on the fracture surface and cracks from the shear lip zone.Additionally,the improvement is reflected by widely distributed voids and prominent slip bands in the longitudinal section of the fracture.The fracture behavior is attributed to the increased high-angle grain boundaries fraction and the reduced dislocation density induced by the appropriate EPT.This microstructure leads to a decrease in texture intensity of the basal plane and an enhancement in crystalline slip capacity of the plane,consequently,the improved plastic deformation capacity of the alloy.展开更多
Elinvar alloys exhibit temperature-independent elastic modulus within a specific temperature range,known as the Elinvar effect,which was first observed in Fe-Ni alloys[1].The unique temperature-independent elastic mod...Elinvar alloys exhibit temperature-independent elastic modulus within a specific temperature range,known as the Elinvar effect,which was first observed in Fe-Ni alloys[1].The unique temperature-independent elastic modulus makes Elinvar alloys highly desirable in precision-control applications,including aerospace,electronics,and optical instruments.Currently,most of the used and studied Elinvar alloys are ferromagnetic alloys(FeNi and Fe-Pt)and antiferromagnetic alloys(Fe-Mn and γ-MnCu)[2–4].The Elinvar effect in these alloys typically originates from magnetostriction or magnetoelastic effects,which are magnetic fieldor magnetic transition-dependent[5].Consequently,these Elinvar alloys cannot function properly in the presence of a magnetic field owing to their Elinvar effect being closely tied to magnetic phase transition.Therefore,developing non-magneticdependent Elinvar alloys is highly essential to widen their practical applications.展开更多
Accurately estimating the battery state of health(SOH)is essential for ensuring the safe and reliable operation of battery systems of electric vehicles.However,due to the complex and variable operating conditions enco...Accurately estimating the battery state of health(SOH)is essential for ensuring the safe and reliable operation of battery systems of electric vehicles.However,due to the complex and variable operating conditions encountered in practical applications,achieving precise and physics-informed SOH estimation remains challenging.To address these problems,this paper develops a lightweight two-stage physicsinformed neural network(TSPINN)method for SOH estimation of lithium-ion batteries with different chemistries.Specifically,this paper utilizes firstly relaxation voltage data obtained after a full charge to determine the aging-related parameters of physical equivalent circuit model(ECM).Additionally,incremental capacity(IC)feature is extracted by analyzing peak values of the IC curve during the charging phase,which thereby constitutes the first stage of the proposed TSPINN,termed as physics-informed data augmentation for SOH estimation.Additionally,the physical information can be further embedded by incorporating feature knowledge related to mechanisms into the loss function,and ultimately,the second stage of the proposed TSPINN is developed,which is named the physics-informed loss function.The effectiveness of the TSPINN method was confirmed through the experimental data for LiNi_(0.86)Co_(0.11)Al_(0.03)O_(2)(NCA)and LiNi_(0.83)Co_(0.11)Mn_(0.07)O_(2)(NCM)battery materials under different temperature conditions.The final experimental results indicate that the TSPINN method achieved SOH estimation with a mean absolute error(MAE)of 0.675%,showing improvements of approximately 29.3%,60.3%,and 8.1% compared to methods using only ECM,IC,and integrated features,respectively.The results validate the effectiveness and adaptability of TSPINN,establishing it as a reliable solution for advanced battery management systems.展开更多
Metastable β-Ti alloys exhibiting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) generally have excellent ductility, but typically at the expense of relatively low yield strengths whi...Metastable β-Ti alloys exhibiting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) generally have excellent ductility, but typically at the expense of relatively low yield strengths which has restricted their widespread use. Our work shows that interstitial oxygen can be employed to regulate β phase stability to significantly enhance both strength and ductility of TWIP/TRIP alloys. For a Ti-32Nb wt.% base alloy, inclusion of 0.3 wt.% O enhanced ductility by more than 140 %, reaching up to 54 % strain, and improved the tensile yield strength by over 95 % to 632 MPa. Compared to other common engineering alloys such as Ti-45Nb, elongation was increased by 29 %, and the yield strength increased by 182 MPa, respectively. Here, we elucidate on impacts of oxygen doping on TWIP/TRIP behaviors in the Ti-32Nb alloy. We reveal that oxygen regulates the critical stress for martensitic transformation, twinning, and dislocation slip. At lower oxygen doping concentrations (≤0.3 wt.% O), multi-stage martensitic transformation and martensitic twinning resulted in high ductility. In higher oxygen content alloys (≥0.5 wt.% O), deformation occurred initially via twinning, while strain induced martensite was subsequently induced in retained β phase regions. Oxygen concentrations control the deformation mechanisms, providing a flexible means to synergistically balance an alloy's strength and ductility. The use of oxygen to enhance stability of the β phase and regulate deformation behaviors is a promising new approach for creating high-performance TWIP/TRIP metastable β-Ti alloys with outstanding mechanical properties.展开更多
The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat...The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat-shrinkable tubing,as a seal on the rock surface,is crucial for reconstructing deep rock in situ conditions(ensuring the accuracy and effectiveness of confining pressure and pore pressure).However,there are few reports on testing such material under HTUP condition.Thus,the mechanical and sealing performances of existing heat-shrinkable tubing under HTUP condition is still immature.The motivation of this study is to advance deep rock mechanics and engineering by developing a polymer heat-shrinkable tubing(pressure larger than 140 MPa and temperature greater than 150℃).Experiments using the deep rock in situ thermal insulation coring test system were conducted and compared with conventional heat-shrinkable tubing.The sealing performance of the polymer heat-shrinkable tubing was investigated.The results indicated that deep rock ultrahigh-pressure condition and natural damage to the rock surface are the main causes of conventional heat-shrinkable tubing failure.In contrast,the damage rate of the proposed polymer heat-shrinkable tubing is extremely low,indicating that incorporating base material with high-performances can significantly enhance the pressure resistance of polymer heat-shrinkable tubing.Additionally,through the analysis of experimental results and the three-dimensional(3D)morphology of rock surfaces,the failure behavior of heat-shrinkable tubing under HTUP condition was revealed at the meso-structural level,and the proposed failure criteria,taking into account 3D morphology of rock surfaces and applicable to HTUP condition,have been advanced.The findings offer possibilities for triaxial rock mechanics testing in HTUP condition,providing theoretical and technical support for experiments and engineering applications in deep rock mechanics.展开更多
The high-temperature conditions of deep oil and gas reservoirs notably affect the porosity and permeability of rocks.In situ temperature-preserved coring(ITP-Coring)technology is crucial for accurately assessing rock ...The high-temperature conditions of deep oil and gas reservoirs notably affect the porosity and permeability of rocks.In situ temperature-preserved coring(ITP-Coring)technology is crucial for accurately assessing rock properties in deep reservoirs.High-performance thermal insulation materials are crucial for supporting ITP-Coring during deep oil and gas exploration.This study explores the impact of high-temperature and high-pressure(HTHP)conditions on hollow glass microsphere/epoxy(HGM/EP)thermal insulation materials,focusing on the interphase.Investigations of HGM/EP materials with varying hollow glass microsphere(HGM)strengths and volume fractions reveal that elevated temperatures cause the molecular chains of the epoxy resin matrix to relax,leading to matrix softening and a decline in mechanical properties.Additionally,high-pressure water infiltrates the material,damaging the interphase and HGMs,further compromising material performance.The combined HTHP environment accelerates this degradation.Dynamic mechanical analysis(DMA)shows that S60HS HGMs,which possess higher strength,interact more strongly with the matrix and exhibit higher entanglement density,resulting in superior interphase adhesion.This enhances stress transfer efficiency and reduces the loss of storage modulus at the interphase.Theoretical analysis indicates that the interphase thickness and modulus of S-f40 remain mostly unaffected after HTHP treatment,with values higher than the epoxy matrix.This correlates with DMA results,demonstrating that S-f40 has the smallest adhesion factor(A),indicating the highest interfacial stress transfer efficiency.S-f40 also exhibits optimal thermal conductivity and mechanical properties,making it ideal for ITP-Coring in deep reservoirs.These findings provide insights for optimizing materials in HTHP environments for deep reservoir exploration.展开更多
In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)proce...In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)process on Ti6Al4V alloy in NaF electrolyte.The influence of NaF concentration(0.15-0.50 mol/L)on the PEO process,microstructure,phase composition,corrosion resistance and thickness of the coatings was investigated using scanning/transmission electron microscopy,energy dispersive spectroscopy,atomic force microscopy,X-ray diffractometer,and potentiodynamic polarization.The results demonstrated that Ti6Al4V alloy had low PEO voltage(less than 200 V)in NaF electrolyte,which decreased further as the NaF concentration increased.A micro/nano-structured coating with 10-15μm pits and 200-800 nm pores was formed in NaF electrolyte;the morphology was different from the typical pancake structure obtained with other electrolytes.The coating formed in NaF electrolyte had low surface roughness and was thin(<4μm).The NaF concentration had a small effect on the phase transition from metastable anatase phase to stable rutile phase,but greatly affected the corrosion resistance.In general,as the NaF concentration increased,the surface roughness,phase(anatase and rutile)contents,corrosion resistance,and thickness of the coating first increased and then decreased,reaching the maximum values at 0.25 mol/L NaF.展开更多
Microarc oxidation(MAO)is an effective surface treatment method for Ti alloys to allow their application in extreme environments.Here,binary electrolytes consisting of different amounts of sodium phosphate and sodium ...Microarc oxidation(MAO)is an effective surface treatment method for Ti alloys to allow their application in extreme environments.Here,binary electrolytes consisting of different amounts of sodium phosphate and sodium silicate were designed for MAO.The surface morphology,composition,and properties of MAO coatings on Ti-6Al-4V alloy treated in 0.10 mol/L electrolyte were investigated to reveal the effect of PO_(4)^(3-)and SiO_(3)^(2-)ray diffraction,and potentiodynamic polarization.The results showed that PO_(4)^(3-)is beneficial for generating microarcs and forming pores within the coating,resulting in a thick but porous coating.SiO_(3)^(2-)eration of microarcs,resulting in a thin dense coating.The thickness,density,phases content,and polarization resistance of the MAO coatings are primarily affected by the intensity of microarcs for low SiO_(3)^(2-)ciently high.The thickness of MAO coatings obtained in P/Si electrolytes shows a piecewise linear increase with increasing process time during the three stages of microarc discharge.SiO_(3)^(2-)discharge,but slows down the growth of the coating formed in the next stage.展开更多
As a promising non-destructive testing(NDT)method,magnetic flux leakage(MFL)testing has been widely used for steel structure inspection.However,MFL testing still faces a great challenge to detect inner defects.Existin...As a promising non-destructive testing(NDT)method,magnetic flux leakage(MFL)testing has been widely used for steel structure inspection.However,MFL testing still faces a great challenge to detect inner defects.Existing MFL course researches mainly focus on surface-breaking defects while that of inner defects is overlooked.In the paper,MFL course of inner defects is investigated by building magnetic circuit models,performing numerical simulations,and conducting MFL experiments.It is found that the near-surface wall has an enhancing effect on the MFL course due to higher permeability of steel than that of air.Further,a high-sensitivity MFL testing method consisting of Helmholtz coil magnetization and induction coil with a high permeability core is proposed to increase the detectable depth of inner defects.Experimental results show that inner defects with buried depth up to 80.0 mm can be detected,suggesting that the proposed MFL method has the potential to detect deeply-buried defects and has a promising future in the field of NDT.展开更多
Cryogenic fracturing with liquid nitrogen(LN_(2))offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing,as well as potentially enhancing the fracture ...Cryogenic fracturing with liquid nitrogen(LN_(2))offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing,as well as potentially enhancing the fracture complexity.We performed a series of laboratory experiments to explore the key mechanisms governing the breakdown pressures of shale during cryogenic fracturing.In this study,cylindrical shale samples were pre-conditioned by exposing a borehole to low-temperature LN_(2) for a certain time period,and then,the samples were fractured using gaseous N_(2) under triaxial stress and a high reservoir temperature.The effects of various key parameters on the breakdown pressure were investigated,including the duration of the low-temperature LN_(2) treatment,the confining pressure,the reservoir temperature,and the direction of the shale bedding relative to the borehole axis.The results demonstrate that the injection of low-temperature LN_(2) as a pre-fracturing fluid into a borehole can significantly reduce the breakdown pressure of the shale during subsequent nitrogen fracturing.This reduction in breakdown pressure can be further intensified by increasing the duration of the LN_(2) pre-conditioning.Without LN_(2) pre-conditioning,the breakdown pressure initially increases and then decreases with increasing reservoir temperature.When LN_(2) pre-conditioning is applied,the breakdown pressure keeps decreasing with increasing reservoir temperature.As the confining pressure increased,the breakdown pressure increased linearly in the tests with and without LN_(2) pre-conditioning.The experimental results demonstrate that LN_(2) preconditioning before N_(2) fracturing is a promising waterless fracturing technique that reduces the breakdown pressure and enhances the fracture complexity.展开更多
基金sponsored by the Science and Technology Program of Hubei Province,China(2022EHB020,2023BBB096)support provided by Centre of the Excellence in Production Research(XPRES)at KTH。
文摘In this review,we propose a comprehensive overview of additive manufacturing(AM)technologies and design possibilities in manufacturing metamaterials for various applications in the biomedical field,of which many are inspired by nature itself.It describes how new AM technologies(e.g.continuous liquid interface production and multiphoton polymerization,etc)and recent developments in more mature AM technologies(e.g.powder bed fusion,stereolithography,and extrusion-based bioprinting(EBB),etc)lead to more precise,efficient,and personalized biomedical components.EBB is a revolutionary topic creating intricate models with remarkable mechanical compatibility of metamaterials,for instance,stress elimination for tissue engineering and regenerative medicine,negative or zero Poisson’s ratio.By exploiting the designs of porous structures(e.g.truss,triply periodic minimal surface,plant/animal-inspired,and functionally graded lattices,etc),AM-made bioactive bone implants,artificial tissues,and organs are made for tissue replacement.The material palette of the AM metamaterials has high diversity nowadays,ranging from alloys and metals(e.g.cobalt-chromium alloys and titanium,etc)to polymers(e.g.biodegradable polycaprolactone and polymethyl methacrylate,etc),which could be even integrated within bioactive ceramics.These advancements are driving the progress of the biomedical field,improving human health and quality of life.
基金Supported by National Natural Science Foundation of China(Grant No.52275206).
文摘Grease is extensively used in rolling bearings due to its inherent sealing properties.However,mechanical degradation typically occurs,resulting in a significantly shorter lifespan for the grease compared to the bearing.Investigating aging mechanisms is essential.This study utilized rolling bearings to obtain mechanically aged greases.The aged samples were then subjected to do rheological test,FTIR test and friction test to examine the effects of aging time,radial load,and rotational speed.An innovative disk-ball-disk device was developed to study the friction characteristics of aged grease in rolling bearings.Additionally,a grease lubrication and friction model were proposed to further evaluate the lubrication performance of aged grease,using measured rheological parameters and the kinematic velocities of the disk-ball-disk device as inputs.The calculated friction coefficients matched well with disk-ball-disk experimental results.FTIR analysis revealed that the non-soap thickener’s structure remained stable,but additives depleted at high speeds.The structure of lithium soap thickener decomposed severely,leading to oil bleeding and a shortened replenishment duration.Over aging time,both greases had lower friction and viscosity due to gradual thickener breakdown,releasing bled oil and extending replenishment.Radial load minimally affected the properties of aged grease.This study may provide valuable insights into the aging mechanisms of grease and the enhancement of rolling bearing lubrication.
基金the financial support from the National Key R&D Program of China(No.2022YFB3706604)the National Natural Science Foundation of China(52304033)+2 种基金the National Natural Science Foundation of China(No.51827901)Sichuan Science and Technology Program(2023NSFSC0790)China Postdoctoral Science Foundation(No.2023M742446)。
文摘A novel temperature-preserved core chamber designed for depths exceeding 5000 m has been developed to enhance the scientific understanding of deep oil and gas reservoirs.This temperature-preserved core chamber employs an innovative vacuum layer for temperature preservation and is compatible with a temperature-pressure preserved coring system.The design principles and key parameters of the temperature-preserved core chamber were determined through static analysis.Numerical simulations assessed the mechanical properties of 70,85,and 100 MPa core chambers under conditions of 120-150℃.The results demonstrate that the temperature-preserved core chambers withstand the applied stresses without plastic deformation,and the vacuum layer maintains its integrity under these conditions.A 70 MPa class core chamber prototype was manufactured,and system integration tests were performed on a self-developed in-situ coring platform.The system demonstrated stable operation at 70 MPa for 120 min,with pressure fluctuations within 5%.Additionally,the integrated system operated without interference,enabling the successful extraction of cores with a 50 mm diameter.These findings provide valuable theoretical guidance and design recommendations for advancing oil and gas in-situ temperature-pressure preserved coring technologies in high-temperature and high-pressure environments.
基金financial support from the National Natural Science Foundation of China(No.52035012)the Guangdong Basic and Applied Basic Research Foundation(No.2025A1515012203)。
文摘The specific surface area(S S)and pore size(D)exhibit an inherent trade-off in the microscale design of bone implants:larger pores typically correlate with reduced surface area and vice versa.This relationship has attracted notable attention because of its critical role in the regulation of cell adhesion and osteogenesis.However,it remains largely unclear how S S and D affect the generated bone tissue and dynamically change during long-term osteogenesis.Herein,by applying rigorous geometric mapping to minimal surfaces,we constructed precisely partitioned and layer-by-layer thickened tissue models to simulate osteogenesis across different temporal scales and thereby track the dynamic evolution of geometric characteristics,permeability,and mechanobiological tissue differentiation.The high-S S samples were found to facilitate the rapid formation of new bone tissue in the early stages.However,their smaller pores tended to cause occlusions,hindering further tissue development.In contrast,low-S S samples showed slower bone regeneration,but their larger pores provided adequate physical space for tissue regeneration and mass transport,ultimately promoting bone formation in the long term.Mechanobiological regulation suggests that fibrous tissue formation inhibits additional bone formation,establishing a dynamic equilibrium between osteogenesis and pore space to sustain nutrient/waste exchange throughout the regenerative process.Overall,smaller pores are preferable in implants for minimally loaded osteoplasty procedures focused on early-stage bone consolidation,whereas larger pores are preferable in dynamically loaded implants requiring prolonged mechanical stability.
基金financially supported by the National Natural Science Foundation of China(Nos.52075351 and 51604177)the National Key Research and Development Program of China(No.2019YFA0705701)+4 种基金the Major S&T Infrastructure Construction Project of Sichuan Province(No.2020-510000-73-01-441847)the International S&T Innovation Cooperation Program of Sichuan Province(No.2020YFH0039)Chengdu International S&T Cooperation Funded Project(Nos.2020-GH02-00006-HZ and 2022-GH02-00027-HZ)the"1000 Talents Plan"of Sichuan Provincethe Talent Introduction Program of Sichuan University(No.YJ201410)。
文摘Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its commercialization.These challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode side.Since the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned issues.In this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and summarized.Crucially,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in detail.Finally,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.
基金supported by the Chinese National Natural Science Fund (No.U1864208)the National Science and Technology Major Project (No.2017-VII-0011-0106)+8 种基金the Youth Science Fund Project of National Natural Science Foundation of China (No.52105396)the Postdoctoral Research Foundation of China (No.2020M682410)Postdoctoral Science and Technology Activity Program of Hubei Province (No.0106110134)the Project Supported by Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing (No.3DL202104)the Science and Technology Planning Project of Tianjin (No.20ZYJDJC00030)the Key Program of Research and Development of Hebei Province (No.202030507040009)the Fund for Innovative Research Groups of Natural Science Foundation of Hebei Province (No.A2020202002)the Natural Science Foundation of Chongqing (No.cstc2021jcyj-msxmX0241)the Key Project of Natural Science Foundation of Tianjin (No.S20ZDF077).
文摘This work systematically studied the effect of volumetric energy density E on the densification,mi-crostructures,tensile mechanical properties,and shape memory performance of a Fe-Mn-Si-Cr-Ni shape memory alloy(SMA)fabricated by laser powder bed fusion(L-PBF).An E of 90-265 J/mm3 is suggested to fabricate the Fe-Mn-Si-Cr-Ni SMA with minor metallurgical defects and a high relative density of above 99%.The increase in E can promote the formation of the primaryγaustenite and the solid phase trans-formation from the primaryδferrite to theγaustenite,which helps to achieve a nearly complete y austenitic microstructure.The increase in E also contributes to fabricating the Fe-Mn-Si-Cr-Ni SMA with superior comprehensive mechanical properties and shape memory performance by L-PBF.The Fe-Mn-Si-Cr-Ni SMA with a combination of good ductility of around 30%,high yield strength of above 480 MPa,an ultrahigh ultimate tensile strength of above 1 GPa,and large recovery strain of about 6%was manu-factured by L-PBF under a high E of 222-250 J/mm^(3).The good shape memory effect,excellent compre-hensive mechanical properties,and low cost of Fe-Mn-Si-Cr-Ni SMAs,as well as the outstanding ability to fabricate complex structures of L-PBF technology,provide a solid foundation for the design and fabri-cation of novel intelligent structures.
基金supported by the National Science and Technology Major Project,China(No.J2019-VII-0013-0153)the Sichuan Science and Technology Program,China(Nos.2021ZDZX0001 and 2021ZDZX0002)。
文摘To enhance the adhesion of ceramic coatings in turbine blade Thermal Barrier Coatings(TBCs)systems,Laser Surface Texturing(LST)was employed to create microstructures on the metal bond coat.The bonding conditions and failure mechanisms of the ceramic coatings within these microstructures were thoroughly investigated.Femtosecond laser technology was used to fabricate three types of high-quality microstructure grooves:linear,sine wave,and grid patterns.These grooves exhibit uniform morphology,well-defined edges,and smooth inner walls.After ceramic coating deposition,columnar crystal structures grew perpendicularly along the groove walls,completely filling the microstructures and forming an arched support structure that significantly enhances mechanical interlocking and adhesion.Among the different microstructures,grid patterns demonstrated the best adhesion performance.In scratch tests,grid-patterned microstructures exhibited only localized small block spalling under high load conditions,avoiding large-scale delamination.This superior performance is attributed to the ability of grid pattern to effectively distribute stress in multiple directions and prevent crack propagation.By reducing stress concentration and enhancing mechanical interlocking points,grid-patterned microstructures also showed excellent resistance to spallation during thermal cycling,markedly improving the thermal resistance and adhesion of coating.
基金financially supported by the Sichuan Science and Technology Program(2022YFS0025 and 2024YFFK0133)supported by the“Fundamental Research Funds for the Central Universities of China.”。
文摘Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static stimuli.Here,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic stimuli.Specifically,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential differences.The controllable and reversible polarization process of the conjugated polymers is fully in situ characterized.Then,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference outputs.Compared with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nW),as well as superior bio-friendliness.As demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning algorithms.This tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.
基金supported by Science and Technology Plan of Luzhou under Grant No.2024JYJ039.
文摘This review systematically summarizes recent advancements in the design of antibacterial hydrogels and the surface-related factors influencing microbial adhesion to polymeric materials.Hydrogels,characterized by their three-dimensional porous architecture and ultra-high water content,serve as ideal platforms for incorporating antibacterial agents(e.g.,metal ions,natural polymers)through physical/chemical interactions,enabling sustained release and enhanced antibacterial efficacy.For traditional polymers,surface properties(e.g.,roughness,charge,superhydrophobicity,free energy,nanoforce gradients)play critical roles in microbial adhesion.Modifying the surface properties of polymers through surface treatment can regulate antibacterial performance.In particular,by referencing the micro/nanostructures found on natural surfaces such as lotus leaves and cicada wings,antibacterial surfaces with multiple superior functions can be fabricated.Collectively,these findings provide a theoretical basis for the rational design of multifunctional antibacterial materials,offering material-based solutions to address complex infection scenarios and advance infection management strategies.
基金financially supported by the National Natural Science Foundation of China(Nos.52075351,51604177)the National Key Research and Development Program of China(No.2019YFA0705701)+4 种基金the National Funded Postdoctoral Researcher Program(No.GZC20231762)the Major S&T Infrastructure Construction Project of Sichuan Province(No.2020-510000-73-01441847)the International S&T Innovation Cooperation Program of Sichuan Province(No.2020YFH0039)the Chengdu International S&T Cooperation Funded Project(Nos.2020-GH02-00006HZ,2022-GH02-00027-HZ)the“1000 Talents Plan”of Sichuan Province,and the Talent Introduction Program of Sichuan University(No.YJ201410)。
文摘Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further application.Herein,from a new perspective,a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth(CC/Ni),which endows the supported active materials with exceptional electronic conductivity and structural stability.In addition,the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components,ensuring the structural integrity of electrodes upon cycling.More importantly,the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical reactions.Therefore,taking Ni_(3)S_(2)nanosheet(Ni_(3)S_(2)NS)anode as an example,the prepared Ni_(3)S_(2)NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm^(2)at 1mA/cm^(2)and high capacity retention of 1.68 mAh/cm^(2)at a high rate of 8mA/cm^(2).This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.
基金financial support from the National Natural Science Foundation of China(No.52205490)the Natural Science Foundation of Sichuan Province,China(No.2022NSFSC0336)。
文摘The effect of electro-pulsing treatment(EPT)with different peak current densities(Jm)on tensile properties of selective laser melting(SLM)-produced TC4 alloy was investigated for significant improvement in the tensile properties of the alloy.When Jm is 30 A/mm2,the elongation is improved distinctly by 19.72%while the ultimate tensile strength remains nearly constant.The improved ductility is evidenced by deeper dimples on the fracture surface and cracks from the shear lip zone.Additionally,the improvement is reflected by widely distributed voids and prominent slip bands in the longitudinal section of the fracture.The fracture behavior is attributed to the increased high-angle grain boundaries fraction and the reduced dislocation density induced by the appropriate EPT.This microstructure leads to a decrease in texture intensity of the basal plane and an enhancement in crystalline slip capacity of the plane,consequently,the improved plastic deformation capacity of the alloy.
基金financially supported by the National Natural Science Foundation of China(No.52401161)the Natural Science Foundation of Sichuan Province for Young Scholars(No.24NSFSC6582)+3 种基金the Postdoctoral Fellowship Program of CPSF(No.GZC20231761)the National Natural Science Foundation of China(No.52271249)the Key Research and Development Program of Shaanxi(No.2023-YBGY-488)the Xi'an Talent Plan(No.XAYC240016).
文摘Elinvar alloys exhibit temperature-independent elastic modulus within a specific temperature range,known as the Elinvar effect,which was first observed in Fe-Ni alloys[1].The unique temperature-independent elastic modulus makes Elinvar alloys highly desirable in precision-control applications,including aerospace,electronics,and optical instruments.Currently,most of the used and studied Elinvar alloys are ferromagnetic alloys(FeNi and Fe-Pt)and antiferromagnetic alloys(Fe-Mn and γ-MnCu)[2–4].The Elinvar effect in these alloys typically originates from magnetostriction or magnetoelastic effects,which are magnetic fieldor magnetic transition-dependent[5].Consequently,these Elinvar alloys cannot function properly in the presence of a magnetic field owing to their Elinvar effect being closely tied to magnetic phase transition.Therefore,developing non-magneticdependent Elinvar alloys is highly essential to widen their practical applications.
基金supported by the Scientific Research and Innovation Team Program of Sichuan University of Science and Engineering(No.SUSE652B005)Anhui Province Applied Peak Discipline Mechanical Engineering(No.XK-XJGF004)。
文摘Accurately estimating the battery state of health(SOH)is essential for ensuring the safe and reliable operation of battery systems of electric vehicles.However,due to the complex and variable operating conditions encountered in practical applications,achieving precise and physics-informed SOH estimation remains challenging.To address these problems,this paper develops a lightweight two-stage physicsinformed neural network(TSPINN)method for SOH estimation of lithium-ion batteries with different chemistries.Specifically,this paper utilizes firstly relaxation voltage data obtained after a full charge to determine the aging-related parameters of physical equivalent circuit model(ECM).Additionally,incremental capacity(IC)feature is extracted by analyzing peak values of the IC curve during the charging phase,which thereby constitutes the first stage of the proposed TSPINN,termed as physics-informed data augmentation for SOH estimation.Additionally,the physical information can be further embedded by incorporating feature knowledge related to mechanisms into the loss function,and ultimately,the second stage of the proposed TSPINN is developed,which is named the physics-informed loss function.The effectiveness of the TSPINN method was confirmed through the experimental data for LiNi_(0.86)Co_(0.11)Al_(0.03)O_(2)(NCA)and LiNi_(0.83)Co_(0.11)Mn_(0.07)O_(2)(NCM)battery materials under different temperature conditions.The final experimental results indicate that the TSPINN method achieved SOH estimation with a mean absolute error(MAE)of 0.675%,showing improvements of approximately 29.3%,60.3%,and 8.1% compared to methods using only ECM,IC,and integrated features,respectively.The results validate the effectiveness and adaptability of TSPINN,establishing it as a reliable solution for advanced battery management systems.
基金supported by the Key R&D Program of Zhejiang(No.KZ7240079).
文摘Metastable β-Ti alloys exhibiting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) generally have excellent ductility, but typically at the expense of relatively low yield strengths which has restricted their widespread use. Our work shows that interstitial oxygen can be employed to regulate β phase stability to significantly enhance both strength and ductility of TWIP/TRIP alloys. For a Ti-32Nb wt.% base alloy, inclusion of 0.3 wt.% O enhanced ductility by more than 140 %, reaching up to 54 % strain, and improved the tensile yield strength by over 95 % to 632 MPa. Compared to other common engineering alloys such as Ti-45Nb, elongation was increased by 29 %, and the yield strength increased by 182 MPa, respectively. Here, we elucidate on impacts of oxygen doping on TWIP/TRIP behaviors in the Ti-32Nb alloy. We reveal that oxygen regulates the critical stress for martensitic transformation, twinning, and dislocation slip. At lower oxygen doping concentrations (≤0.3 wt.% O), multi-stage martensitic transformation and martensitic twinning resulted in high ductility. In higher oxygen content alloys (≥0.5 wt.% O), deformation occurred initially via twinning, while strain induced martensite was subsequently induced in retained β phase regions. Oxygen concentrations control the deformation mechanisms, providing a flexible means to synergistically balance an alloy's strength and ductility. The use of oxygen to enhance stability of the β phase and regulate deformation behaviors is a promising new approach for creating high-performance TWIP/TRIP metastable β-Ti alloys with outstanding mechanical properties.
基金funding provided by the National Natural Science Foundation of China(Grant Nos.51827901 and 52174084)the Natural Science Foundation of Sichuan Provence,China(Grant No.2022NSFSC0005).
文摘The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat-shrinkable tubing,as a seal on the rock surface,is crucial for reconstructing deep rock in situ conditions(ensuring the accuracy and effectiveness of confining pressure and pore pressure).However,there are few reports on testing such material under HTUP condition.Thus,the mechanical and sealing performances of existing heat-shrinkable tubing under HTUP condition is still immature.The motivation of this study is to advance deep rock mechanics and engineering by developing a polymer heat-shrinkable tubing(pressure larger than 140 MPa and temperature greater than 150℃).Experiments using the deep rock in situ thermal insulation coring test system were conducted and compared with conventional heat-shrinkable tubing.The sealing performance of the polymer heat-shrinkable tubing was investigated.The results indicated that deep rock ultrahigh-pressure condition and natural damage to the rock surface are the main causes of conventional heat-shrinkable tubing failure.In contrast,the damage rate of the proposed polymer heat-shrinkable tubing is extremely low,indicating that incorporating base material with high-performances can significantly enhance the pressure resistance of polymer heat-shrinkable tubing.Additionally,through the analysis of experimental results and the three-dimensional(3D)morphology of rock surfaces,the failure behavior of heat-shrinkable tubing under HTUP condition was revealed at the meso-structural level,and the proposed failure criteria,taking into account 3D morphology of rock surfaces and applicable to HTUP condition,have been advanced.The findings offer possibilities for triaxial rock mechanics testing in HTUP condition,providing theoretical and technical support for experiments and engineering applications in deep rock mechanics.
基金This work was funded by the National Natural Science Foun-dation of China(No.52304033)the National Key Research and Development Program of China(No.2023YFB2390200)Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization(No.DESGEEU-2023-10).
文摘The high-temperature conditions of deep oil and gas reservoirs notably affect the porosity and permeability of rocks.In situ temperature-preserved coring(ITP-Coring)technology is crucial for accurately assessing rock properties in deep reservoirs.High-performance thermal insulation materials are crucial for supporting ITP-Coring during deep oil and gas exploration.This study explores the impact of high-temperature and high-pressure(HTHP)conditions on hollow glass microsphere/epoxy(HGM/EP)thermal insulation materials,focusing on the interphase.Investigations of HGM/EP materials with varying hollow glass microsphere(HGM)strengths and volume fractions reveal that elevated temperatures cause the molecular chains of the epoxy resin matrix to relax,leading to matrix softening and a decline in mechanical properties.Additionally,high-pressure water infiltrates the material,damaging the interphase and HGMs,further compromising material performance.The combined HTHP environment accelerates this degradation.Dynamic mechanical analysis(DMA)shows that S60HS HGMs,which possess higher strength,interact more strongly with the matrix and exhibit higher entanglement density,resulting in superior interphase adhesion.This enhances stress transfer efficiency and reduces the loss of storage modulus at the interphase.Theoretical analysis indicates that the interphase thickness and modulus of S-f40 remain mostly unaffected after HTHP treatment,with values higher than the epoxy matrix.This correlates with DMA results,demonstrating that S-f40 has the smallest adhesion factor(A),indicating the highest interfacial stress transfer efficiency.S-f40 also exhibits optimal thermal conductivity and mechanical properties,making it ideal for ITP-Coring in deep reservoirs.These findings provide insights for optimizing materials in HTHP environments for deep reservoir exploration.
文摘In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)process on Ti6Al4V alloy in NaF electrolyte.The influence of NaF concentration(0.15-0.50 mol/L)on the PEO process,microstructure,phase composition,corrosion resistance and thickness of the coatings was investigated using scanning/transmission electron microscopy,energy dispersive spectroscopy,atomic force microscopy,X-ray diffractometer,and potentiodynamic polarization.The results demonstrated that Ti6Al4V alloy had low PEO voltage(less than 200 V)in NaF electrolyte,which decreased further as the NaF concentration increased.A micro/nano-structured coating with 10-15μm pits and 200-800 nm pores was formed in NaF electrolyte;the morphology was different from the typical pancake structure obtained with other electrolytes.The coating formed in NaF electrolyte had low surface roughness and was thin(<4μm).The NaF concentration had a small effect on the phase transition from metastable anatase phase to stable rutile phase,but greatly affected the corrosion resistance.In general,as the NaF concentration increased,the surface roughness,phase(anatase and rutile)contents,corrosion resistance,and thickness of the coating first increased and then decreased,reaching the maximum values at 0.25 mol/L NaF.
基金financially supported by China Postdoctoral Science Foundation (No.2021M700569)Chongqing Postdoctoral Science Foundation (No.cstc2021jcyj-bsh0133)
文摘Microarc oxidation(MAO)is an effective surface treatment method for Ti alloys to allow their application in extreme environments.Here,binary electrolytes consisting of different amounts of sodium phosphate and sodium silicate were designed for MAO.The surface morphology,composition,and properties of MAO coatings on Ti-6Al-4V alloy treated in 0.10 mol/L electrolyte were investigated to reveal the effect of PO_(4)^(3-)and SiO_(3)^(2-)ray diffraction,and potentiodynamic polarization.The results showed that PO_(4)^(3-)is beneficial for generating microarcs and forming pores within the coating,resulting in a thick but porous coating.SiO_(3)^(2-)eration of microarcs,resulting in a thin dense coating.The thickness,density,phases content,and polarization resistance of the MAO coatings are primarily affected by the intensity of microarcs for low SiO_(3)^(2-)ciently high.The thickness of MAO coatings obtained in P/Si electrolytes shows a piecewise linear increase with increasing process time during the three stages of microarc discharge.SiO_(3)^(2-)discharge,but slows down the growth of the coating formed in the next stage.
基金Supported by National Natural Science Foundation of China(Grant Nos.51907131,92060114)Sichuan Science and Technology Program(Grant Nos.2020YFG0090,2021YFG0039,2020ZDZX0024).
文摘As a promising non-destructive testing(NDT)method,magnetic flux leakage(MFL)testing has been widely used for steel structure inspection.However,MFL testing still faces a great challenge to detect inner defects.Existing MFL course researches mainly focus on surface-breaking defects while that of inner defects is overlooked.In the paper,MFL course of inner defects is investigated by building magnetic circuit models,performing numerical simulations,and conducting MFL experiments.It is found that the near-surface wall has an enhancing effect on the MFL course due to higher permeability of steel than that of air.Further,a high-sensitivity MFL testing method consisting of Helmholtz coil magnetization and induction coil with a high permeability core is proposed to increase the detectable depth of inner defects.Experimental results show that inner defects with buried depth up to 80.0 mm can be detected,suggesting that the proposed MFL method has the potential to detect deeply-buried defects and has a promising future in the field of NDT.
基金This work was supported by the National Natural Science Foundation of China(No.51674247)the project for Fundamental Research Funds for the Central Universities(China University of Mining and Technology)under No.2015XKZD06.
文摘Cryogenic fracturing with liquid nitrogen(LN_(2))offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing,as well as potentially enhancing the fracture complexity.We performed a series of laboratory experiments to explore the key mechanisms governing the breakdown pressures of shale during cryogenic fracturing.In this study,cylindrical shale samples were pre-conditioned by exposing a borehole to low-temperature LN_(2) for a certain time period,and then,the samples were fractured using gaseous N_(2) under triaxial stress and a high reservoir temperature.The effects of various key parameters on the breakdown pressure were investigated,including the duration of the low-temperature LN_(2) treatment,the confining pressure,the reservoir temperature,and the direction of the shale bedding relative to the borehole axis.The results demonstrate that the injection of low-temperature LN_(2) as a pre-fracturing fluid into a borehole can significantly reduce the breakdown pressure of the shale during subsequent nitrogen fracturing.This reduction in breakdown pressure can be further intensified by increasing the duration of the LN_(2) pre-conditioning.Without LN_(2) pre-conditioning,the breakdown pressure initially increases and then decreases with increasing reservoir temperature.When LN_(2) pre-conditioning is applied,the breakdown pressure keeps decreasing with increasing reservoir temperature.As the confining pressure increased,the breakdown pressure increased linearly in the tests with and without LN_(2) pre-conditioning.The experimental results demonstrate that LN_(2) preconditioning before N_(2) fracturing is a promising waterless fracturing technique that reduces the breakdown pressure and enhances the fracture complexity.
