Valve-regulated-lead-acid (VRLA) battery charging performed in high-temperature environments is extremely risky under overcharge conditions, and may lead to a subsequent thermal runaway. A new pressure-controlled char...Valve-regulated-lead-acid (VRLA) battery charging performed in high-temperature environments is extremely risky under overcharge conditions, and may lead to a subsequent thermal runaway. A new pressure-controlled charging method was adopted and the charging characteristics of the pressure-controlled VRLA battery in high-temperature environments were ex-perimentally studied. The concept was tested in a large temperature gradient to obtain more details about the effects of users' accustomed charging and discharging modes on battery capacity. The premature capacity loss (PCL) phenomenon under high temperature exposure was analyzed. The results showed that the capacity loss could be recovered by charging using a large current.展开更多
In the fields of optoelectronics and semiconductors, reliable fixation and handling of brittle materials (glass, wafer, etc.) in high-temperature, vacuum, and vibration environments face particular technical challenge...In the fields of optoelectronics and semiconductors, reliable fixation and handling of brittle materials (glass, wafer, etc.) in high-temperature, vacuum, and vibration environments face particular technical challenges. These challenges include the inability of suction cups in a vacuum, the residue of chemical adhesives, and the easy damage of mechanical clamping. In this paper, fluorine-based bionic adhesive pads (FBAPs) obtained using molding technology to imitate gecko micropillar arrays are presented. FBAPs inhibit the substantial decay of adhesive properties at high temperatures and provide stable and reliable performance in vacuum and vibration environments. The results demonstrated that the decayed force values of the normal and tangential strength of the FBAP were only 9.01% and 5.82% of the planar samples when warmed up to 300℃ from 25℃, respectively. In a vacuum, all FBAPs exhibit less than 20% adhesion attenuation, and in a vibrational environment, they can withstand accelerations of at least 4.27 g. The design of the microstructure arrays enables the realization of efficient and non-destructive separation through mechanical rotation or blowing. It provides a bionic material basis for the fixation of brittle materials on smooth surfaces under complex environments and for transportation automation.展开更多
Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a c...Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a certain gradation or proportion.This type of concrete is highly suitable for modern construction waste disposal and reuse and has been widely used in various construction projects.It can also be used as an environmentally friendly permeable brick material to promote the development of modern green buildings.However,practical applications have found that compared to ordinary concrete,the durability of this type of concrete is more susceptible to high-temperature and complex environments.Based on this,this paper conducts theoretical research on its durability in high-temperature and complex environments,including the current research status,existing problems,and application prospects of recycled aggregate concrete’s durability in such environments.It is hoped that this analysis can provide some reference for studying the influence of high-temperature and complex environments on recycled aggregate concrete and its subsequent application strategies.展开更多
This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standar...This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standard system was established for comprehensive quality evaluation of HTD.There were obvious changes in the physicochemical properties,enzyme activities,and volatile flavor components at different storage periods,which affected the sensory evaluation of HTD to a certain extent.The results of high-throughput sequencing revealed significant microbial diversity,and showed that the bacterial community changed significantly more than did the fungal community.During the storage process,the dominant bacterial genera were Kroppenstedtia and Thermoascus.The correlation between dominant microorganisms and quality indicators highlighted their role in HTD quality.Lactococcus,Candida,Pichia,Paecilomyces,and protease activity played a crucial role in the formation of isovaleraldehyde.Acidic protease activity had the greatest impact on the microbial community.Moisture promoted isobutyric acid generation.Furthermore,the comprehensive quality evaluation standard system was established by the entropy weight method combined with multi-factor fuzzy mathematics.Consequently,this study provides innovative insights for comprehensive quality evaluation of HTD during storage and establishes a groundwork for scientific and rational storage of HTD and quality control of sauce-flavor Baijiu.展开更多
High-temperature industries,as the primary consumers of energy,are greatly concerned with energy savings.Designing refractory linings with low thermal conductivity to reduce heat dissipation through high-temperature f...High-temperature industries,as the primary consumers of energy,are greatly concerned with energy savings.Designing refractory linings with low thermal conductivity to reduce heat dissipation through high-temperature furnace linings is a critical concern.In this study,a series of novel entropy-stabilized spinel materials are reported,and their potential applications in high-temperature industries are investigated.XRD and TEM results indicate that all materials possess a cubic spinel crystal structure with the■space group.Furthermore,these materials exhibit good phase stability at high temperatures.All entropy-stabilized spinel aggregates demonstrated high refractoriness(>1800℃)and a high load softening temperature(>1700℃).The impact of configurational entropy on the properties of entropy-stabilized spinel materials was also studied.As configurational entropy increased,the thermal conductivity of the entropy-stabilized spinel decreased,while slag corrosion resistance deteriorated.For the entropy-stabilized spinel with a configurational entropy value of 1.126R,it showed good high-temperature stability,reliable resistance to slag attack,and a low thermal conductivity of 2.776 W·m^(-1)·K^(-1)at 1000℃.展开更多
Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temper...Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.展开更多
High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density,but they still suffer from structural instability and detrimental side reactions wit...High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density,but they still suffer from structural instability and detrimental side reactions with the solid-state electrolytes.To circumvent these issues,a continuous uniform layer polyacrylonitrile(PAN)was introduced on the surface of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) via in situ polymerization of acrylonitrile(AN).Furthermore,the partial-cyclized treatment of PAN(cPAN)coating layer presents high ionic and electron conductivity,which can accelerate interfacial Li+and electron diffusion simultaneously.And the thermodynamically stabilized cPAN coating layer cannot only effectively inhibit detrimental side reactions between cathode and solid-state electrolytes but also provide a homogeneous stress to simultaneously address the problems of bulk structural degradation,which contributes to the exceptional mechanical and electrochemical stabilities of the modified electrode.Besides,the coordination bond interaction between the cPAN and NCM811 can suppress the migration of Ni to elevate the stability of the crystal structure.Benefited from these,the In-cPAN-260@NCM811 shows excellent cycling performance with a retention of 86.8%after 300 cycles and superior rate capability.And endow the solid-state battery with thermal safety stability even at hightemperature extreme environment.This facile and scalable surface engineering represents significant progress in developing high-performance solid-state lithium metal batteries.展开更多
The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity.Herein,the lightweight silicon carbide nanowires(S...The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity.Herein,the lightweight silicon carbide nanowires(SiC_(nws))/SiC composites are fabricated with in-situ SiC interface on one-dimensional oriented SiC_(nws)skeleton,which collaborative configuration by 3D printing and freeze casting assembly.The con-structed porous structure optimizes the impedance matching degree and scattering intensity,the maximum effective absorption bandwidth(EAB_(max))of 5.9 GHz and the minimum reflection loss(RL_(min))of−41.4 dB can be realized.Considering the inherent oxidation resistance of SiC,the composites present well-maintained absorption performance at 600℃.Even at 1100℃,the EAB_(max)of 4.9 GHz and RLmin of−30.4 dB also demonstrate the high-temperature absorption stability of the composites,indicating exceptional wave absorption properties and thermal stability.The slight attenuation can be attributed to the decrease in impedance matching capability accompanying the elevated dielectric constant.This work clarifies the impact of structure and component synergy on wave absorption behavior,and offers a novel approach to producing high-performance and high-temperature resistance ceramic-based electromagnetic wave absorption materials suitable for extreme environments.展开更多
Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose har...Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose hardness is 65 HRC and flexural strength is 1450 MPa.The high-temperature oxidation mechanism of TiC-based cermets was investigated through an X-ray diffractometer and scanning electron microscope.The added elements Ni and Cr along with their solid solutions not only bond with the hard phase TiC to ensure the physical performance of the cermet,but also impede the internal diffusion during oxidation by forming a dense composite oxide layer,thereby enhancing the oxidation resistance.The TiC-NiCr cermet exhibits a dense protective oxide layer at 900℃ and can endure continuous oxidation for approximately 1000 h.A methodology for fabricating TiC-NiCr metal matrix composites is proposed,and their oxidation resistance is evaluated,providing a theoretical and practical basis for simultaneously enhancing the mechanical properties and oxidation resistance and reducing production costs.展开更多
To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions tha...To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.展开更多
High-temperature piezoelectric sen-sors are very important in severe environments such as fire safety,aerospace and oil drills,however,most current sensors are not heat res-istant(<300℃)and are fragile,which limit...High-temperature piezoelectric sen-sors are very important in severe environments such as fire safety,aerospace and oil drills,however,most current sensors are not heat res-istant(<300℃)and are fragile,which limits their use,especially in high-temperature environ-ments.A high-temperature resistant flexible piezoelectric film based on graphene oxide(GO)/polyacrylonitrile(PAN)composites was prepared by electrospinning and thermal treat-ment.It was packed into a micro-device,which could work continuously at 500℃.The intro-duction of GO significantly increased the mechanical properties of the PAN nanofibers because the oxygen-containing func-tional groups(electronegative groups)on the surface of the GO initiated a nucleophilic attack on the PAN molecule during heat treatment,enabling the GO to initiate the cyclization of the PAN at lower heat-treatment temperatures.In addition,the abund-ant oxygen-containing functional groups on GO acted as pro-oxidants to hasten the oxidation of PAN during heat treatment.The effects of GO content and heat treatment temperature on the properties of the nanofiber films were investigated.A GO/PAN nanofiber piezoelectric sensor heat-treated at 300℃had a 9.10 V and 2.25μA peak output,which are respectively 101.3%and 78.6%higher than those of the untreated films.Cyclic testing over 5000 cycles at 350℃confirmed the stable out-put performance of the GO/PAN nanofiber piezoelectric sensor.Furthermore,a sensor heat-treated at 400℃had a sensitivity of 1.7 V/N,which is 83.5%higher than that of an untreated one.The results show that the prepared GO/PAN nanofiber piezo-electric sensor combines high temperature resistance,high flexibility,stability and high sensitivity,and may have broad applic-ations in high temperature environments such as the aerospace and petroleum industries.展开更多
(TiZrHf)_(50)Ni_(30)Cu_(20-x)Co_(x)(x=2,4,6,at%)high-entropy high-temperature shape memory alloys were fabricated by watercooled copper crucible in a magnetic levitation vacuum melting furnace,and the effects of Co co...(TiZrHf)_(50)Ni_(30)Cu_(20-x)Co_(x)(x=2,4,6,at%)high-entropy high-temperature shape memory alloys were fabricated by watercooled copper crucible in a magnetic levitation vacuum melting furnace,and the effects of Co content on microstructure and mechanical properties were investigated.The results indicate that the grain size of the alloy decreases with increasing the Co content.In the as-cast state,the alloy consists primarily of the B19′phase,with a trace of B2 phase.The fracture morphology is predominantly composed of the B19′phase,whereas the B2 phase is nearly absent.Increasing the Co content or reducing the sample dimensions(d)markedly enhance the compressive strength and ductility of the alloy.When d=2 mm,the(TiZrHf)_(50)Ni_(30)Cu_(14)Co_(6) alloy demonstrates the optimal mechanical properties,achieving a compressive strength of 2142.39±1.8 MPa and a plasticity of 17.31±0.3%.The compressive cyclic test shows that with increasing the compressive strain,the residual strain of the(TiZrHf)_(50)Ni_(30)Cu_(14)Co_(6) alloy increases while the recovery ability declines.The superelastic recovery capability of the alloy is continuously enhanced.The superelastic recovery rate increases from 1.36%to 2.12%,the residual strain rate rises from 1.79%to 5.52%,the elastic recovery rate ascends from 3.86%to 7.36%,while the total recovery rate declines from 74.48%to 63.20%.展开更多
To improve the high-temperature oxidation resistance of TiAlNb9 alloy,a Cr-Al-Y co-deposition coating was prepared on the alloy surface by the pack cementation method.The microstructure of the coating was analyzed by ...To improve the high-temperature oxidation resistance of TiAlNb9 alloy,a Cr-Al-Y co-deposition coating was prepared on the alloy surface by the pack cementation method.The microstructure of the coating was analyzed by scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer,and the high-temperature oxidation properties of the substrate and coating at 1273 K were compared and studied.The results show that the Cr-Al-Y coating is about 30μm in thickness,and it has a dense structure and good film-substrate bonding.The coating includes an outer layer composed of TiCr_(2),TiCr,Ti4Cr,and(Ti,Nb)Cr4 phases as well as an inner layer composed of Ti_(2)Al,and Nb-richγ-TiAl interdiffusion zone.The TiAlNb9 substrate forms an oxide layer composed of TiO2 and Al_(2)O_(3) at 1273 K.Due to its loose and porous structure,TiO2 oxide film cannot effectively isolate the internal diffusion of element O,resulting in continuous oxidation damage to the substrate.The Cr-Al-Y co-deposition coating forms a dense Cr2O3 and Al_(2)O_(3) oxide layer during oxidation,effectively preventing the internal diffusion of element O and significantly improving the high-temperature oxidation resistance of the substrate alloy.展开更多
Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,a...Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.展开更多
Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework n...Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework named the Formation Interfered Fluid Dynamical System(FIFDS) with Moderate Evasive Maneuver Strategy(MEMS) is proposed in this study.First, the UAV formation collision avoidance problem including quantifiable performance indexes is formulated. Second, inspired by the phenomenon of fluids continuously flowing while bypassing objects, the FIFDS for multiple UAVs is presented, which contains a Parallel Streamline Tracking(PST) method for formation keeping and the traditional IFDS for collision avoidance. Third, to rationally balance flight safety and collision avoidance cost, MEMS is proposed to generate moderate evasive maneuvers that match up with collision risks. Comprehensively containing the time and distance safety information, the 3-D dynamic collision regions are modeled for collision prediction. Then, the moderate evasive maneuver principle is refined, which provides criterions of the maneuver amplitude and direction. On this basis, an analytical parameter mapping mechanism is designed to online optimize IFDS parameters. Finally, the performance of the proposed method is validated by comparative simulation results and real flight experiments using fixed-wing UAVs.展开更多
Conformal thin-film sensors enable precise monitoring of the operating conditions of components in extreme environments.However,the development of these sensors encounters major challenges,especially in uniformly appl...Conformal thin-film sensors enable precise monitoring of the operating conditions of components in extreme environments.However,the development of these sensors encounters major challenges,especially in uniformly applying multiple film layers on complex metallic surfaces and accurately capturing diverse operational parameters.This work reports a multi-sensor design and multi-layer additive manufacturing process targeting spherical metallic substrates.The proposed high-temperature dip-coating and self-leveling fabrication process achieves high-temperature thin-film coatings with excellent uniformity,high-temperature electrical insulation,and adhesion properties.The fabricated Ag/Pt thin film thermocouple arrays and a heat flux sensor exhibit a maximum temperature resistance of up to 960℃,with thermoelectric potential outputs and hightemperature resistance closely mirroring those of wire-based Ag/Pt thermocouples.Harsh environmental testing was conducted using high-power lasers and a flame gun.The results show that the array of thin-film conformal thermocouples more accurately reflected temperature changes at different points on a spherical surface.The heat flux sensors achieve responses within 95 ms and with-stand environments with heat fluxes over 1.2 MW/m^(2).The proposed multi-sensor design and fabrication method offers promising monitoring applications in harsh environments,including aerospace and nuclear power.展开更多
The tensile strength of rocks under real-time high-temperatures is essential for enhanced geothermal system development.However,the complex occurrence and deep burial of hot dry rocks limit the quantity and quality of...The tensile strength of rocks under real-time high-temperatures is essential for enhanced geothermal system development.However,the complex occurrence and deep burial of hot dry rocks limit the quantity and quality of standard samples for mechanical testing.This paper compared the tensile strengths obtained from Brazilian splitting tests on standard samples(with a diameter of 50 mm and a thickness of 25 mm)and micro-tensile samples(with a diameter of 50 mm and a thickness of 25 mm)of two types of granites.A power-law size effect model was established between the two sets of data,validating the reliability of the testing method.Then,miniature Brazilian splitting under real-time high-temperature,combined with X-ray diffraction(XRD)revealed temperature-dependent strength variations and microstructural damage mechanisms.The results show that:(1)The comparison error between the tensile strength obtained by the fitting model and that of the measured standard samples was less than 6%.(2)In real-time high-temperature conditions,tensile strength of granite exhibited non-monotonic behavior,increasing below 300°C before decreasing,with sharp declines at 400–500°C and 600–700°C.(3)Thermal damage stems from the differences in the high-temperature behavior of minerals,including dehydration,phase transformation,and differential expansion.展开更多
With the rapid advancement of science and technology,along with an increasing global focus on space exploration,there is a growing concern for addressing friction and wear issues in surface coatings for components ope...With the rapid advancement of science and technology,along with an increasing global focus on space exploration,there is a growing concern for addressing friction and wear issues in surface coatings for components operating in high-temperature environments within the aerospace sector.However,typical high-temperature coatings currently face challenges in effectively integrating excellent oxidation resistance,wear resistance,and lubrication properties in high-temperature settings.Studies have demonstrated the significant potential of Transition Metal Dichalcogenides(TMDCs)as lubricant additives in high-temperature lubrication,attributable to their distinctive crystal structures.Thus,this review concentrates on the compositional design of individual MX_(2)-type(M=W,Mo,Nb,Ta;X=S,Se)TMDCs(molybdenum disulfide(MoS_(2)),tungsten disulfide(WS2),niobium diselenide(NbSe_(2)),molybdenum diselenide(MoSe_(2)),tungsten diselenide(WSe_(2)))and their composites,including inorganic oxygen-containing sulfides,and explores the utilization of TMDCs in self-lubricating coatings.Furthermore,conventional preparation methods(mechanical exfoliation,liquid-phase ultrasonic exfoliation,chemical vapour deposition)for synthesizing TMDCs are outlined.Finally,an analysis of the lubrication mechanism of MX_(2)-type TMDCs is provided,along with future directions for enhancing the high-temperature lubrication performance of composite coatings.展开更多
Investigating highly effective electrocatalysts for high-temperature proton exchange membrane fuel cells(HT-PEMFC)requires the resistance to phosphate acid(PA)poisoning at cathodic oxygen reduction reaction(ORR).Recen...Investigating highly effective electrocatalysts for high-temperature proton exchange membrane fuel cells(HT-PEMFC)requires the resistance to phosphate acid(PA)poisoning at cathodic oxygen reduction reaction(ORR).Recent advancements in catalysts have focused on alleviating phosphoric anion adsorption on Pt-based catalysts with modified electronic structure or catalytic interface and developing Fe-N-C based catalysts with immunity of PA poisoning.Fe-N-C-based catalysts have emerged as promising alternatives to Pt-based catalysts,offering significant potential to overcome the characteristic adsorption of phosphate anion on Pt.An overview of these developments provides insights into catalytic mechanisms and facilitates the design of more efficient catalysts.This review begins with an exploration of basic poisoning principles,followed by a critical summary of characterization techniques employed to identified the underlying mechanism of poisoning effect.Attention is then directed to endeavors aimed at enhancing the HT-PEMFC performance by well-designed catalysts.Finally,the opportunities and challenges in developing the anti-PA poisoning strategy and practical HT-PEMFC is discussed.Through these discussions,a comprehensive understanding of PA-poisoning bottlenecks and inspire future research directions is aim to provided.展开更多
The high-temperature deformation and dynamic recrystallization(DRX)behaviors of GH4698 superalloy were investigated via hot compression tests,and an improved unified dislocation density-based constitutive model was es...The high-temperature deformation and dynamic recrystallization(DRX)behaviors of GH4698 superalloy were investigated via hot compression tests,and an improved unified dislocation density-based constitutive model was established.The results indicate that with the temperature decreasing or the strain rate increasing,the flow stress increases and the DRX fraction decreases.However,as the strain rate increases from 1 to 10 s^(-1),rapid dislocation multiplication and deformation heat accelerate the DRX nucleation,which further increases the DRX fraction.Discontinuous DRX nucleation is the dominant DRX nucleation mechanism,and continuous DRX nucleation mainly occurs under low strain rates.For the developed improved unified dislocation density-based constitutive model,the correlation coefficient,average absolute relative error,and root mean square error between the measured and predicted stresses are 0.994,7.32%and 10.8 MPa,respectively.Meanwhile,the correlation coefficient between the measured and predicted DRX fractions is 0.976.These indicate that the developed model exhibits high accuracy in predicting the high-temperature deformation and DRX behaviors of GH4698 superalloy.展开更多
文摘Valve-regulated-lead-acid (VRLA) battery charging performed in high-temperature environments is extremely risky under overcharge conditions, and may lead to a subsequent thermal runaway. A new pressure-controlled charging method was adopted and the charging characteristics of the pressure-controlled VRLA battery in high-temperature environments were ex-perimentally studied. The concept was tested in a large temperature gradient to obtain more details about the effects of users' accustomed charging and discharging modes on battery capacity. The premature capacity loss (PCL) phenomenon under high temperature exposure was analyzed. The results showed that the capacity loss could be recovered by charging using a large current.
基金supported by the National Natural Science Foundation of China(No.52075249)the Tianyuan Laboratory Fund(No.24-JSKY-ZZKT-14).
文摘In the fields of optoelectronics and semiconductors, reliable fixation and handling of brittle materials (glass, wafer, etc.) in high-temperature, vacuum, and vibration environments face particular technical challenges. These challenges include the inability of suction cups in a vacuum, the residue of chemical adhesives, and the easy damage of mechanical clamping. In this paper, fluorine-based bionic adhesive pads (FBAPs) obtained using molding technology to imitate gecko micropillar arrays are presented. FBAPs inhibit the substantial decay of adhesive properties at high temperatures and provide stable and reliable performance in vacuum and vibration environments. The results demonstrated that the decayed force values of the normal and tangential strength of the FBAP were only 9.01% and 5.82% of the planar samples when warmed up to 300℃ from 25℃, respectively. In a vacuum, all FBAPs exhibit less than 20% adhesion attenuation, and in a vibrational environment, they can withstand accelerations of at least 4.27 g. The design of the microstructure arrays enables the realization of efficient and non-destructive separation through mechanical rotation or blowing. It provides a bionic material basis for the fixation of brittle materials on smooth surfaces under complex environments and for transportation automation.
基金Chongqing Municipal Education Commission Science and Technology Research Project(Project No.KJQN202301910).
文摘Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a certain gradation or proportion.This type of concrete is highly suitable for modern construction waste disposal and reuse and has been widely used in various construction projects.It can also be used as an environmentally friendly permeable brick material to promote the development of modern green buildings.However,practical applications have found that compared to ordinary concrete,the durability of this type of concrete is more susceptible to high-temperature and complex environments.Based on this,this paper conducts theoretical research on its durability in high-temperature and complex environments,including the current research status,existing problems,and application prospects of recycled aggregate concrete’s durability in such environments.It is hoped that this analysis can provide some reference for studying the influence of high-temperature and complex environments on recycled aggregate concrete and its subsequent application strategies.
文摘This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standard system was established for comprehensive quality evaluation of HTD.There were obvious changes in the physicochemical properties,enzyme activities,and volatile flavor components at different storage periods,which affected the sensory evaluation of HTD to a certain extent.The results of high-throughput sequencing revealed significant microbial diversity,and showed that the bacterial community changed significantly more than did the fungal community.During the storage process,the dominant bacterial genera were Kroppenstedtia and Thermoascus.The correlation between dominant microorganisms and quality indicators highlighted their role in HTD quality.Lactococcus,Candida,Pichia,Paecilomyces,and protease activity played a crucial role in the formation of isovaleraldehyde.Acidic protease activity had the greatest impact on the microbial community.Moisture promoted isobutyric acid generation.Furthermore,the comprehensive quality evaluation standard system was established by the entropy weight method combined with multi-factor fuzzy mathematics.Consequently,this study provides innovative insights for comprehensive quality evaluation of HTD during storage and establishes a groundwork for scientific and rational storage of HTD and quality control of sauce-flavor Baijiu.
基金financially supported by the National Natural Science Foundation of China(Nos.52472032 and 52172023)the Key Program of Natural Science Foundation of Hubei Province(No.2024AFA083)
文摘High-temperature industries,as the primary consumers of energy,are greatly concerned with energy savings.Designing refractory linings with low thermal conductivity to reduce heat dissipation through high-temperature furnace linings is a critical concern.In this study,a series of novel entropy-stabilized spinel materials are reported,and their potential applications in high-temperature industries are investigated.XRD and TEM results indicate that all materials possess a cubic spinel crystal structure with the■space group.Furthermore,these materials exhibit good phase stability at high temperatures.All entropy-stabilized spinel aggregates demonstrated high refractoriness(>1800℃)and a high load softening temperature(>1700℃).The impact of configurational entropy on the properties of entropy-stabilized spinel materials was also studied.As configurational entropy increased,the thermal conductivity of the entropy-stabilized spinel decreased,while slag corrosion resistance deteriorated.For the entropy-stabilized spinel with a configurational entropy value of 1.126R,it showed good high-temperature stability,reliable resistance to slag attack,and a low thermal conductivity of 2.776 W·m^(-1)·K^(-1)at 1000℃.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2062)supported by the Key Laboratory for Carbonate Reservoirs of China National Petroleum Corporation。
文摘Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.
基金financially supported by the National Natural Science Foundation of China(Nos.22102212 and 22479067).
文摘High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density,but they still suffer from structural instability and detrimental side reactions with the solid-state electrolytes.To circumvent these issues,a continuous uniform layer polyacrylonitrile(PAN)was introduced on the surface of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) via in situ polymerization of acrylonitrile(AN).Furthermore,the partial-cyclized treatment of PAN(cPAN)coating layer presents high ionic and electron conductivity,which can accelerate interfacial Li+and electron diffusion simultaneously.And the thermodynamically stabilized cPAN coating layer cannot only effectively inhibit detrimental side reactions between cathode and solid-state electrolytes but also provide a homogeneous stress to simultaneously address the problems of bulk structural degradation,which contributes to the exceptional mechanical and electrochemical stabilities of the modified electrode.Besides,the coordination bond interaction between the cPAN and NCM811 can suppress the migration of Ni to elevate the stability of the crystal structure.Benefited from these,the In-cPAN-260@NCM811 shows excellent cycling performance with a retention of 86.8%after 300 cycles and superior rate capability.And endow the solid-state battery with thermal safety stability even at hightemperature extreme environment.This facile and scalable surface engineering represents significant progress in developing high-performance solid-state lithium metal batteries.
基金supported by the National Key R&D Program of China(No.2022YFB3707700)National Natural Science Foundation of China(No.52302121)+3 种基金Shanghai Sailing Program(No.23YF1454700)Shanghai Natural Science Foundation(No.23ZR1472700)Shanghai Post-doctoral Excellent Program(No.2022664)Shanghai Science and Technology Innovation Action Plan(No.21511104800).
文摘The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity.Herein,the lightweight silicon carbide nanowires(SiC_(nws))/SiC composites are fabricated with in-situ SiC interface on one-dimensional oriented SiC_(nws)skeleton,which collaborative configuration by 3D printing and freeze casting assembly.The con-structed porous structure optimizes the impedance matching degree and scattering intensity,the maximum effective absorption bandwidth(EAB_(max))of 5.9 GHz and the minimum reflection loss(RL_(min))of−41.4 dB can be realized.Considering the inherent oxidation resistance of SiC,the composites present well-maintained absorption performance at 600℃.Even at 1100℃,the EAB_(max)of 4.9 GHz and RLmin of−30.4 dB also demonstrate the high-temperature absorption stability of the composites,indicating exceptional wave absorption properties and thermal stability.The slight attenuation can be attributed to the decrease in impedance matching capability accompanying the elevated dielectric constant.This work clarifies the impact of structure and component synergy on wave absorption behavior,and offers a novel approach to producing high-performance and high-temperature resistance ceramic-based electromagnetic wave absorption materials suitable for extreme environments.
基金National Natural Science Foundation of China(52376076)Open Fund of Material Corrosion and Protection Key Laboratory of Sichuan Province(2023CL13)Laiwu Vocational and Technical College Teachers Research Fund(2023jsky05)。
文摘Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose hardness is 65 HRC and flexural strength is 1450 MPa.The high-temperature oxidation mechanism of TiC-based cermets was investigated through an X-ray diffractometer and scanning electron microscope.The added elements Ni and Cr along with their solid solutions not only bond with the hard phase TiC to ensure the physical performance of the cermet,but also impede the internal diffusion during oxidation by forming a dense composite oxide layer,thereby enhancing the oxidation resistance.The TiC-NiCr cermet exhibits a dense protective oxide layer at 900℃ and can endure continuous oxidation for approximately 1000 h.A methodology for fabricating TiC-NiCr metal matrix composites is proposed,and their oxidation resistance is evaluated,providing a theoretical and practical basis for simultaneously enhancing the mechanical properties and oxidation resistance and reducing production costs.
基金supported by the Beijing Natural Science Foundation(No.L212029)the National Natural Science Foundation of China(No.62271043).
文摘To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.
文摘High-temperature piezoelectric sen-sors are very important in severe environments such as fire safety,aerospace and oil drills,however,most current sensors are not heat res-istant(<300℃)and are fragile,which limits their use,especially in high-temperature environ-ments.A high-temperature resistant flexible piezoelectric film based on graphene oxide(GO)/polyacrylonitrile(PAN)composites was prepared by electrospinning and thermal treat-ment.It was packed into a micro-device,which could work continuously at 500℃.The intro-duction of GO significantly increased the mechanical properties of the PAN nanofibers because the oxygen-containing func-tional groups(electronegative groups)on the surface of the GO initiated a nucleophilic attack on the PAN molecule during heat treatment,enabling the GO to initiate the cyclization of the PAN at lower heat-treatment temperatures.In addition,the abund-ant oxygen-containing functional groups on GO acted as pro-oxidants to hasten the oxidation of PAN during heat treatment.The effects of GO content and heat treatment temperature on the properties of the nanofiber films were investigated.A GO/PAN nanofiber piezoelectric sensor heat-treated at 300℃had a 9.10 V and 2.25μA peak output,which are respectively 101.3%and 78.6%higher than those of the untreated films.Cyclic testing over 5000 cycles at 350℃confirmed the stable out-put performance of the GO/PAN nanofiber piezoelectric sensor.Furthermore,a sensor heat-treated at 400℃had a sensitivity of 1.7 V/N,which is 83.5%higher than that of an untreated one.The results show that the prepared GO/PAN nanofiber piezo-electric sensor combines high temperature resistance,high flexibility,stability and high sensitivity,and may have broad applic-ations in high temperature environments such as the aerospace and petroleum industries.
基金National Natural Science Foundation of China(12404230,52061027)Science and Technology Program Project of Gansu Province(22YF7GA155)+1 种基金Lanzhou Youth Science and Technology Talent Innovation Project(2023-QN-91)Zhejiang Provincial Natural Science Foundation of China(LY23E010002)。
文摘(TiZrHf)_(50)Ni_(30)Cu_(20-x)Co_(x)(x=2,4,6,at%)high-entropy high-temperature shape memory alloys were fabricated by watercooled copper crucible in a magnetic levitation vacuum melting furnace,and the effects of Co content on microstructure and mechanical properties were investigated.The results indicate that the grain size of the alloy decreases with increasing the Co content.In the as-cast state,the alloy consists primarily of the B19′phase,with a trace of B2 phase.The fracture morphology is predominantly composed of the B19′phase,whereas the B2 phase is nearly absent.Increasing the Co content or reducing the sample dimensions(d)markedly enhance the compressive strength and ductility of the alloy.When d=2 mm,the(TiZrHf)_(50)Ni_(30)Cu_(14)Co_(6) alloy demonstrates the optimal mechanical properties,achieving a compressive strength of 2142.39±1.8 MPa and a plasticity of 17.31±0.3%.The compressive cyclic test shows that with increasing the compressive strain,the residual strain of the(TiZrHf)_(50)Ni_(30)Cu_(14)Co_(6) alloy increases while the recovery ability declines.The superelastic recovery capability of the alloy is continuously enhanced.The superelastic recovery rate increases from 1.36%to 2.12%,the residual strain rate rises from 1.79%to 5.52%,the elastic recovery rate ascends from 3.86%to 7.36%,while the total recovery rate declines from 74.48%to 63.20%.
基金National Natural Science Foundation of China(52161009)Innovation Project of Postgraduate Students in North Minzu University(YCX24104)。
文摘To improve the high-temperature oxidation resistance of TiAlNb9 alloy,a Cr-Al-Y co-deposition coating was prepared on the alloy surface by the pack cementation method.The microstructure of the coating was analyzed by scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer,and the high-temperature oxidation properties of the substrate and coating at 1273 K were compared and studied.The results show that the Cr-Al-Y coating is about 30μm in thickness,and it has a dense structure and good film-substrate bonding.The coating includes an outer layer composed of TiCr_(2),TiCr,Ti4Cr,and(Ti,Nb)Cr4 phases as well as an inner layer composed of Ti_(2)Al,and Nb-richγ-TiAl interdiffusion zone.The TiAlNb9 substrate forms an oxide layer composed of TiO2 and Al_(2)O_(3) at 1273 K.Due to its loose and porous structure,TiO2 oxide film cannot effectively isolate the internal diffusion of element O,resulting in continuous oxidation damage to the substrate.The Cr-Al-Y co-deposition coating forms a dense Cr2O3 and Al_(2)O_(3) oxide layer during oxidation,effectively preventing the internal diffusion of element O and significantly improving the high-temperature oxidation resistance of the substrate alloy.
基金National Natural Science Foundation of China(52071126)Natural Science Foundation of Tianjin City,China(22JCQNJC01240)+2 种基金Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z1009G)Special Funds for Science and Technology Innovation in Hebei(2022X19)Anhui Provincial Natural Science Foundation(2308085ME135)。
文摘Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.
基金supported in part by the National Natural Science Foundations of China(Nos.61175084,61673042 and 62203046)the China Postdoctoral Science Foundation(No.2022M713006).
文摘Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework named the Formation Interfered Fluid Dynamical System(FIFDS) with Moderate Evasive Maneuver Strategy(MEMS) is proposed in this study.First, the UAV formation collision avoidance problem including quantifiable performance indexes is formulated. Second, inspired by the phenomenon of fluids continuously flowing while bypassing objects, the FIFDS for multiple UAVs is presented, which contains a Parallel Streamline Tracking(PST) method for formation keeping and the traditional IFDS for collision avoidance. Third, to rationally balance flight safety and collision avoidance cost, MEMS is proposed to generate moderate evasive maneuvers that match up with collision risks. Comprehensively containing the time and distance safety information, the 3-D dynamic collision regions are modeled for collision prediction. Then, the moderate evasive maneuver principle is refined, which provides criterions of the maneuver amplitude and direction. On this basis, an analytical parameter mapping mechanism is designed to online optimize IFDS parameters. Finally, the performance of the proposed method is validated by comparative simulation results and real flight experiments using fixed-wing UAVs.
基金supported by the National Key Research and Development Program of China(No.2022YFB3203900)。
文摘Conformal thin-film sensors enable precise monitoring of the operating conditions of components in extreme environments.However,the development of these sensors encounters major challenges,especially in uniformly applying multiple film layers on complex metallic surfaces and accurately capturing diverse operational parameters.This work reports a multi-sensor design and multi-layer additive manufacturing process targeting spherical metallic substrates.The proposed high-temperature dip-coating and self-leveling fabrication process achieves high-temperature thin-film coatings with excellent uniformity,high-temperature electrical insulation,and adhesion properties.The fabricated Ag/Pt thin film thermocouple arrays and a heat flux sensor exhibit a maximum temperature resistance of up to 960℃,with thermoelectric potential outputs and hightemperature resistance closely mirroring those of wire-based Ag/Pt thermocouples.Harsh environmental testing was conducted using high-power lasers and a flame gun.The results show that the array of thin-film conformal thermocouples more accurately reflected temperature changes at different points on a spherical surface.The heat flux sensors achieve responses within 95 ms and with-stand environments with heat fluxes over 1.2 MW/m^(2).The proposed multi-sensor design and fabrication method offers promising monitoring applications in harsh environments,including aerospace and nuclear power.
基金supported by the National Natural Science Foundation of China(Nos.52174175 and 52274078)the Program for the Scientific and Technological Innovation Team in Universities of Henan Province(No.23IRTSTHN005)。
文摘The tensile strength of rocks under real-time high-temperatures is essential for enhanced geothermal system development.However,the complex occurrence and deep burial of hot dry rocks limit the quantity and quality of standard samples for mechanical testing.This paper compared the tensile strengths obtained from Brazilian splitting tests on standard samples(with a diameter of 50 mm and a thickness of 25 mm)and micro-tensile samples(with a diameter of 50 mm and a thickness of 25 mm)of two types of granites.A power-law size effect model was established between the two sets of data,validating the reliability of the testing method.Then,miniature Brazilian splitting under real-time high-temperature,combined with X-ray diffraction(XRD)revealed temperature-dependent strength variations and microstructural damage mechanisms.The results show that:(1)The comparison error between the tensile strength obtained by the fitting model and that of the measured standard samples was less than 6%.(2)In real-time high-temperature conditions,tensile strength of granite exhibited non-monotonic behavior,increasing below 300°C before decreasing,with sharp declines at 400–500°C and 600–700°C.(3)Thermal damage stems from the differences in the high-temperature behavior of minerals,including dehydration,phase transformation,and differential expansion.
文摘With the rapid advancement of science and technology,along with an increasing global focus on space exploration,there is a growing concern for addressing friction and wear issues in surface coatings for components operating in high-temperature environments within the aerospace sector.However,typical high-temperature coatings currently face challenges in effectively integrating excellent oxidation resistance,wear resistance,and lubrication properties in high-temperature settings.Studies have demonstrated the significant potential of Transition Metal Dichalcogenides(TMDCs)as lubricant additives in high-temperature lubrication,attributable to their distinctive crystal structures.Thus,this review concentrates on the compositional design of individual MX_(2)-type(M=W,Mo,Nb,Ta;X=S,Se)TMDCs(molybdenum disulfide(MoS_(2)),tungsten disulfide(WS2),niobium diselenide(NbSe_(2)),molybdenum diselenide(MoSe_(2)),tungsten diselenide(WSe_(2)))and their composites,including inorganic oxygen-containing sulfides,and explores the utilization of TMDCs in self-lubricating coatings.Furthermore,conventional preparation methods(mechanical exfoliation,liquid-phase ultrasonic exfoliation,chemical vapour deposition)for synthesizing TMDCs are outlined.Finally,an analysis of the lubrication mechanism of MX_(2)-type TMDCs is provided,along with future directions for enhancing the high-temperature lubrication performance of composite coatings.
文摘Investigating highly effective electrocatalysts for high-temperature proton exchange membrane fuel cells(HT-PEMFC)requires the resistance to phosphate acid(PA)poisoning at cathodic oxygen reduction reaction(ORR).Recent advancements in catalysts have focused on alleviating phosphoric anion adsorption on Pt-based catalysts with modified electronic structure or catalytic interface and developing Fe-N-C based catalysts with immunity of PA poisoning.Fe-N-C-based catalysts have emerged as promising alternatives to Pt-based catalysts,offering significant potential to overcome the characteristic adsorption of phosphate anion on Pt.An overview of these developments provides insights into catalytic mechanisms and facilitates the design of more efficient catalysts.This review begins with an exploration of basic poisoning principles,followed by a critical summary of characterization techniques employed to identified the underlying mechanism of poisoning effect.Attention is then directed to endeavors aimed at enhancing the HT-PEMFC performance by well-designed catalysts.Finally,the opportunities and challenges in developing the anti-PA poisoning strategy and practical HT-PEMFC is discussed.Through these discussions,a comprehensive understanding of PA-poisoning bottlenecks and inspire future research directions is aim to provided.
基金supported by the National Natural Science Foundation of China(No.52375337)the Key Research and Development Program of Hubei Province,China(No.2022BAA024)the Fundamental Research Funds for the Central Universities,China(No.2019kfyXJJS001).
文摘The high-temperature deformation and dynamic recrystallization(DRX)behaviors of GH4698 superalloy were investigated via hot compression tests,and an improved unified dislocation density-based constitutive model was established.The results indicate that with the temperature decreasing or the strain rate increasing,the flow stress increases and the DRX fraction decreases.However,as the strain rate increases from 1 to 10 s^(-1),rapid dislocation multiplication and deformation heat accelerate the DRX nucleation,which further increases the DRX fraction.Discontinuous DRX nucleation is the dominant DRX nucleation mechanism,and continuous DRX nucleation mainly occurs under low strain rates.For the developed improved unified dislocation density-based constitutive model,the correlation coefficient,average absolute relative error,and root mean square error between the measured and predicted stresses are 0.994,7.32%and 10.8 MPa,respectively.Meanwhile,the correlation coefficient between the measured and predicted DRX fractions is 0.976.These indicate that the developed model exhibits high accuracy in predicting the high-temperature deformation and DRX behaviors of GH4698 superalloy.
