The effect of real-time high temperature and thermal treatment on the mechanical characteristics and crack evolution of granite with different grain sizes(i.e.,0.5 mm,0.7 mm and 1.0 mm)is investigated by numerical sim...The effect of real-time high temperature and thermal treatment on the mechanical characteristics and crack evolution of granite with different grain sizes(i.e.,0.5 mm,0.7 mm and 1.0 mm)is investigated by numerical simulation employing a grain-based model,and the impact of initial cracks on thermal-induced strengthening is also examined by integrating random cracks within the model before tests.The results revealed that thermal stress,induced by the mismatch in thermal expansion coefficient between various minerals,is the primary distinction between rock specimens in real-time high temperature and thermal treatment.With increasing temperature,the thermal stress gradually accumulates in quartz minerals under real-time high temperature but releases after thermal treatment.The high local contact force significantly affects the peak stress and crack evolution.Uniaxial compression simulation results demonstrate that progressive accumulation of thermal stress induces degradation in macroscopic peak strength and increase of microcrack density.The grain size controls the ratio of intergranular contacts to intragranular contacts,and leads to an increase in strong contact number in the intragrain and a decrease in strong contact number in the intergrain.The strengthening of uniaxial compression strength in the experiment can be well simulated by controlling the number of pre-existing initial cracks in the numerical model.Our conclusions are beneficial to a better understanding of the underlying mechanisms of thermal damage and thermal strengthening of granite for deep geological engineering.展开更多
High temperature stress (HT) significantly reduces maize yield by impairing starch accumulation in kernels.However,the mechanism by which HT affects starch synthesis remains controversial-whether through reduced assim...High temperature stress (HT) significantly reduces maize yield by impairing starch accumulation in kernels.However,the mechanism by which HT affects starch synthesis remains controversial-whether through reduced assimilate supply or direct inhibition on kernel metabolism.To clarify these mechanisms,a heat-sensitive maize hybrid,Xianyu 335 (XY),was exposed to 30℃/20℃ (maximum/minimum temperature,control) and 40℃/30℃ for seven consecutive days during the seed setting stage.Synchronous pollination (SP),apical pollination (AP),and shading treatments were applied to manipulate the inherent source–sink ratio in maize plants.Results showed that apical kernel weight decreased by 11.9%under 40℃ in the SP treatment.The ^(13)C content,starch accumulation,and cell-wall invertase (CWIN) activity also declined by 15.9,36.7,and 16.4%,respectively,under HT.In the shading treatment,40℃/30℃ caused even greater reductions in^(13)C content,starch accumulation,and CWIN activity due to diminished assimilate supply.Conversely,in the AP treatment,starch content and CWIN activity increased by 22.0 and 18.5%,respectively,under 40℃/30℃,resulting in kernel weight and ^(13)C content similar to those in SP and shading treatments regardless of temperature.Consistent with apical kernels under AP,HT did not negatively affect middle kernels in either SP or shading treatments,as kernel weight and starch content remained unchanged under HT.Although all kernels were exposed to the same HT or control environment,their responses varied a lot.The impaired starch synthesis in apical kernels under HT was rescued by increasing carbon supply via AP treatment.The contrasting performance among middle kernels,apical kernels under AP,and apical kernels under SP or shading indicates that reduced carbon supply is a critical factor underlying inhibited starch accumulation.Our findings provide a theoretical basis for further understanding kernel abortion under HT.展开更多
Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on thes...Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on these characteristics.This study aimed to characterize spikelet filling in early-season rice and identify the key factors contributing to its improvement.Field experiments were conducted over two years(2021 and 2022)to mainly investigate the proportions of fully-filled,partially-filled,and empty spikelets,along with the biomass-fertilized spikelet ratio and harvest index,in 11 early-season rice varieties.The results revealed significant varietal variation in spikelet filling,with the proportion of fully-filled spikelets ranging from 60.6%to 81.1%in 2021 and from 66.3%to 79.2%in 2022.Among the 11 varieties,Liangyou 42,Lingliangyou 942,and Liangyou 287 exhibited relatively superior performance in spikelet filling.Linear regression revealed that,although a significant negative relationship existed between the proportion of fully-filled spikelets and both partially-filled and empty spikelets,the relationship with partially-filled spikelets was stronger.Additionally,the proportion of fully-filled spikelets showed a significant positive relationship with the harvest index but not with the biomass-fertilized spikelet ratio.These findings indicate that increasing the harvest index and reducing the occurrence of partially-filled grains are essential strategies for improving spikelet filling in early-season rice.展开更多
CO_(2)flooding enhanced oil recovery(CO_(2)-EOR)represents a significant technology in the low permeability reservoir.With the fractures and heterogeneity in low permeability reservoirs,CO_(2)-EOR is susceptible to pe...CO_(2)flooding enhanced oil recovery(CO_(2)-EOR)represents a significant technology in the low permeability reservoir.With the fractures and heterogeneity in low permeability reservoirs,CO_(2)-EOR is susceptible to pessimistic gas channeling.Consequently,there is a need to develop conformance control materials that can be used in CO_(2)-EOR.Herein,to address the challenges of low strength and poor stability of polymer gel in high temperature and low permeability reservoirs,a new organic/metal ion composite crosslinking polymer gel(AR-Gel)is reported,which is formed by low hydrolysis and medium to high molecular weight polymer(CX-305),organic crosslinking agent(phenolic resin),and aluminium citrate(AI(Ⅲ)).The crosslinking of AI(Ⅲ)with carboxyl group and organic/metal ion double crosslinking can construct a more complex and stable polymer gel structure on the basis of traditional chemical crosslinking,to cope with the harsh conditions such as high temperature.The structure-activity relationship of AR-Gel was revealed by rheology behavior and micro-morphology.The applicability of AR-Gel in reservoir was investigated,as was its strength and stability in supercritical CO_(2).The anti-gas channeling and enhanced oil recovery of AR-Gel were investigated using low permeability fractured cores,and the field process parameters were provided.The gel can be used to meet supercritical CO_(2)reservoirs at 110℃and 20,000 mg/L salinity,with long-term stability over 60 days.The plugging rate of AR-Gel for fractured co re was 97%,with subsequent CO_(2)flooding re sulting in an enhanced oil recovery by 34.5%.ARGel can effectively control CO_(2)gas channeling and enhanced oil recovery.It offers a new material with high strength and temperature resistance,which is particularly beneficial in the CO_(2)flooding for the conformance control of oil field.展开更多
The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle o...The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles.展开更多
Polymer dielectrics possessing excellent electrical insulation and high thermal conductivity are pivotal for dielectric capacitors at elevated temperatures.However,the integration of electrical insulation and thermal ...Polymer dielectrics possessing excellent electrical insulation and high thermal conductivity are pivotal for dielectric capacitors at elevated temperatures.However,the integration of electrical insulation and thermal conductivity in polymers remains a challenge.In this work,we present a feasible strategy to integrate high electrical insulation and high thermal conductivity by bonding carbon quantum dots(CQDs)with the diamine monomer of polyetherimide(PEI).The CQDs with Coulomb blockade effect serve as traps for the migrating of electrons in the dielectrics,while the bonding networks formed by CQDs and PEI further deepen the traps and augment trap density.As a result,the hybrid dielectrics(PEI-NH_(2)-CQDs)exhibit nearly an order of magnitude higher electrical resistivity than that of pure PEI,leading to an 80%increase in discharge energy density with an energy efficiency of 90%at 200℃ compared to pure counterpart.Additionally,this all-organic dielectric achieves a significantly increased thermal conductivity of 0.65 W m^(-1) K^(-1) compared to 0.26 W m^(-1) K^(-1) of PEI,which supports its cyclic stability at elevated temperatures.We also demonstrate the kilogram-scale production of CQDs,synthesizing over 8 kg in a single batch,paving the way for large-scale production of reliable PEI-NH_(2)-CQDs dielectrics.展开更多
Gallium nitride(GaN)single crystal with prominent electron mobility and heat resistance have great potential in the high temperature integrate electric power systems.However,the sluggish charge storage kinetics and in...Gallium nitride(GaN)single crystal with prominent electron mobility and heat resistance have great potential in the high temperature integrate electric power systems.However,the sluggish charge storage kinetics and inadequate energy densities are bottlenecks to its practical application.Herein,the self-supported GaN/Mn_(3)O_(4) integrated electrode is developed for both energy harvesting and storage under the high temperature environment.The experimental and theoretical calculations results reveal that such integrated structures with Mn-N heterointerface bring abundant active sites and reconstruct low-energy barrier channels for efficient charge transferring,reasonably optimizing the ions adsorption ability and strengthening the structural stability.Consequently,the assembled GaN based supercapacitors deliver the power density of 34.0 mW cm^(-2) with capacitance retention of 81.3%after 10000 cycles at 130℃.This work innovatively correlates the centimeter scale GaN single crystal with ideal theoretical capacity Mn_(3)O_(4) and provides an effective avenue for the follow-up energy storage applications of the wide bandgap semiconductor.展开更多
Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production eff...Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production efficiency of shale oil resources.Effectively stimulating oil shale reservoirs remains a challenging and active research topic.This investigation employed shale specimens obtained from the Longmaxi Formation.Scanning electron microscopy,fluid injection experiments,and fluid-structure interaction simulations were used to comprehensively analyze structural changes and fluid flow behavior under high temperatures from microscopic to macroscopic scales.Experimental results indicate that the temperature has little effect on the structure and permeability of shale before 300℃.However,there are two threshold temperatures within the range of 300 to 600℃that have significant effects on the structure and permeability of oil shale.The first threshold temperature is between 300 and 400℃,which causes the oil shale porosity,pore-fracture ratio,and permeability begin to increase.This is manifested by the decrease in micropores and mesopores,the increase in macropores,and the formation of a large number of isolated pores and fissures within the shale.The permeability increases but not significantly.The second threshold temperature is between 500 and 600℃,which increases the permeability of oil shale significantly.During this stage,micropores and mesopores are further reduced,and macropores are significantly enlarged.A large number of connected and penetrated pores and fissures are formed.More numerous and thicker streamlines appear inside the oil shale.The experimental results demonstrate that high temperatures significantly alter the microstructure and permeability of oil shale.At the same time,the experimental results can provide a reference for the research of in-situ heating techniques in oil shale reservoir transformation.展开更多
The active development of space industry necessitates the cre-ation of novel materials with unique properties,including shape memory alloys(SMAs).The development of ultra-high temperature SMAs(UHTSMAs)with operating t...The active development of space industry necessitates the cre-ation of novel materials with unique properties,including shape memory alloys(SMAs).The development of ultra-high temperature SMAs(UHTSMAs)with operating temperatures above 400℃is a significant challenge[1-3].It is known that reversible thermoelas-tic martensitic transformation(MT)is the basis for shape mem-ory behavior[4].Currently,there are several systems in which MT temperatures meet the above requirements,for example,RuNb[5],HfPd[6],TiPd[7].展开更多
This work investigated the anisotropy tensile properties of Inconel 625 alloy fabricated by laser powder bed fusion (LPBF) under various tests temperature, focusing the anisotropy evolution during the high temperature...This work investigated the anisotropy tensile properties of Inconel 625 alloy fabricated by laser powder bed fusion (LPBF) under various tests temperature, focusing the anisotropy evolution during the high temperature. The microstructure contained columnar grains with (111) texture in the vertical plane (90° sample), while a large equiaxed grain with (100) texture was produced in the horizontal plane (0° sample). As for 45° sample, a large number of equiaxed grains and a few columnar grains with (111) texture can be observed. The sample produced at a 0° orientation demonstrates the highest tensile strength, whereas the 90° sample exhibits the greatest elongation. Conversely, the 45° sample displays the least favorable overall performance. As the tests temperature increased from room temperature to 600℃, the anisotropy rate of ultimate tensile strength, yield strength and ductility between 0° and 45° samples, decreased from 8.98 to 6.96%, 2.36 to 1.28%, 19.93 to 12.23%, as well as between 0° and 90° samples decreased from 4.87 to 4.03%, 11.88 to 7.21% and 14.11 to 6.89%, respectively, because of the recovery of oriented columnar grains.展开更多
Electrocatalytic reduction of carbon dioxide(CO_(2))to carbon monoxide(CO)is an effective strategy to achieve carbon neutrality.High selective and low-cost catalysts for the electrocatalytic reduction of CO_(2)have re...Electrocatalytic reduction of carbon dioxide(CO_(2))to carbon monoxide(CO)is an effective strategy to achieve carbon neutrality.High selective and low-cost catalysts for the electrocatalytic reduction of CO_(2)have received increasing attention.In contrast to the conventional tube furnace method,the high-temperature shock(HTS)method enables ultra-fast thermal processing,superior atomic efficiency,and a streamlined synthesis protocol,offering a simplified method for the preparation of high-performance single-atom catalysts(SACs).The reports have shown that nickel-based SACs can be synthesized quickly and conveniently using the HTS method,making their application in CO_(2)reduction reactions(CO_(2)RR)a viable and promising avenue for further exploration.In this study,the effect of heating temperature,metal loading and different nitrogen(N)sources on the catalyst morphology,coordination environment and electrocatalytic performance were investigated.Under optimal conditions,0.05Ni-DCD-C-1050 showed excellent performance in reducing CO_(2)to CO,with CO selectivity close to 100%(−0.7 to−1.0 V vs RHE)and current density as high as 130 mA/cm^(2)(−1.1 V vs RHE)in a flow cell under alkaline environment.展开更多
High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications,but the trade-off between energy density and temperature stability remains fundamentally c...High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications,but the trade-off between energy density and temperature stability remains fundamentally challenging.Here,we report a general material design strategy to enhance energy storage performance at high temperatures by crosslinking a polar polymer and a high glass-transition temperature polymer as a crosslinked binary blend.Such crosslinked binary polymers display a temperature-insensitive and high energy density behavior of about6.2~8.5 J cm^(-3) up to 110℃,showing a significant enhancement in thermal resistant properties and consequently outperforming most of the other ferroelectric polymers.Further microstructural investigations reveal that the improved thermal stability stems from the confinement effect on conformational motion of the crosslinking network,which is evidenced by the increased rigid amorphous fraction and steady intermolecular distance of amorphous regions from temperature-dependent X-ray diffraction results.Our findings provide a general and straightforward strategy to attain temperature-stable,high-energy-density polymer-based dielectrics for energy storage capacitors.展开更多
The performance of welded Ni-based superalloys at high temperatures is essential to be evaluated due to their particular service environment for aero-engines and high-speed aircrafts.The tensile properties and related...The performance of welded Ni-based superalloys at high temperatures is essential to be evaluated due to their particular service environment for aero-engines and high-speed aircrafts.The tensile properties and related microstructural evolutions such as the carbide precipitate and grain of a laser-welded Ni-based alloy were experimentally and numerically investigated at different temperatures(20,300,500,800℃).The results show that at room temperature,the strength of the Base Material(BM)was slightly smaller,with a difference of less than 1%,than the Welded Material(WM),which can be attributed to the more uniformly distributed needle-shaped carbide precipitates in the WM than those nonuniformly coarser spherical ones in the BM.While at 300℃ and 500℃,the strength of WM decreased more obviously compared with that of BM due to the more apparent growth of grain:13.52%loss in yield strength in WM alloys as compared with BM alloys at 300℃,and 16.57% at 500℃.At 800℃,the strength of BM and WM both decreased to a similar level due to Dynamic Recrystallization(DRX).However,a much higher elongation was observed for the BM than WM(less than 50%of BM),which can be attributed to the enhanced dislocation accumulation capability of the large spherical carbides along grain boundaries on the fracture surface in BM.Furthermore,a unified model considering the welding effects on both microstructures(dislocation,carbides,and grain)and mechanical properties evolutions at different temperatures was developed and validated.Based on this model,the key temperature ranges(20–600℃)where apparent weakening of strength and uniform plasticity occurs for welded structures were identified,providing a direct guidance for potential structure and process design.展开更多
The interface pressure between cables and accessories plays a crucial role in the long-term reliable operation of cable systems.However,the change in interface pressure at high temperature and its influencing mechanis...The interface pressure between cables and accessories plays a crucial role in the long-term reliable operation of cable systems.However,the change in interface pressure at high temperature and its influencing mechanism are still inconclusive.In this study,the changes of interface pressure at high temperature mainly caused by three influencing factors were investigated through theoretical analysis and experimental measurements.The results revealed that the thermal expansion effect will result in a decrease in interface pressure,while the Gough-Joule effect of rubber materials at high temperature will lead to an increase in interface pressure as the temperature rises.Additionally,the stress relaxation effect of rubber-like materials at high temperature will accelerate the decline in interface pressure.Finally,a calculation method for interface pressure based on the comprehensive effect of these factors is proposed.The results showed that the interface pressure increases as the temperature rises,indicating that the Gough-Joule effect of rubber materials dominates the change in interface pressure.The error between the theoretical calculation and actual measurement of interface pressure was<5%.Therefore,this method can feasibly be used to evaluate the interface pressure in the medium-voltage(MV)and even high-voltage(HV)integral prefabricated cable accessories as the temperature changes.展开更多
High-nickel cathode LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)could enable lithium-ion batteries(LIBs)with high energy density.However,excessive decomposition of the electrolyte would happen in the high operating voltage...High-nickel cathode LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)could enable lithium-ion batteries(LIBs)with high energy density.However,excessive decomposition of the electrolyte would happen in the high operating voltage range.In addition,the utilization of flammable organic solvents would increase safety risks in the high temperature environment.Herein,an electrolyte consisting of flame-retardant solvents with lower highest occupied molecular orbital(HOMO)level and LiDFOB salt is proposed to address above two issues.As a result,a thin and robust cathode-electrolyte interface containing rich LiF and Li-B-O compounds is formed on the cathode to effectively suppress electrolyte decomposition in the high operating voltage.The NCM811||Li cell paired with this designed electrolyte possesses a capacity retention of 72%after 300 cycles at 55℃.This work provides insights into developing electrolyte for stable high-nickel cathode operated in the high temperature.展开更多
Within the framework of carbon neutrality,lithium-ion batteries(LIBs)are progressively booming along with the growing utilization of green and clean energy.However,the extensive application of LIBs with limited lifesp...Within the framework of carbon neutrality,lithium-ion batteries(LIBs)are progressively booming along with the growing utilization of green and clean energy.However,the extensive application of LIBs with limited lifespan has brought about a significant recycling dilemma.The traditional hydrometallurgical or pyrometallurgical strategies are not capable to maximize the output value of spent LIBs and minimize the potential environmental hazards.Herein,to alternate the tedious and polluting treatment processes,we propose a high-temperature molten-salt strategy to directly regenerate spent cathodes of LIBs,which can also overcome the barrier of the incomplete defects'restoration with previous low-temperature molten salts.The high-energy and stable medium environment ensures a more thorough and efficient relithiation reaction,and simultaneously provides sufficient driving force for atomic rearrangement and grains secondary growth.In consequence,the regenerated ternary cathode(R-NCM)exhibits significantly enhanced structural stability that effectively suppresses the occurrence of cracks and harmful side reactions.The R-NCM delivers excellent cycling stability,retaining 81.2%of its capacity after 200 cycles at 1 C.This technique further optimizes the traditional eutectic molten-salt approach,broadening its applicability and improving regenerated cathode performance across a wider range of conditions.展开更多
Ultrahigh pressure generation at high temperatures is technologically challenging for large sample volumes.In this study,we successfully generated pressures of 37.3-40.4 GPa at 1900-2100 K in a Walker-type large-volum...Ultrahigh pressure generation at high temperatures is technologically challenging for large sample volumes.In this study,we successfully generated pressures of 37.3-40.4 GPa at 1900-2100 K in a Walker-type large-volume press(LVP).Expansion of the pressure range at high temperatures was achieved by adapting newly designed ZK01F tungsten carbide(WC)anvils with tapered surfaces and using cell assemblies with an^(-1) mm^(3) sample volume and hard materials,as well as by applying certain adjustments to the apparatus.The pressure efficiencies of the different types of WC anvils and cell assemblies were also studied.Using the above-mentioned techniques,we successfully synthesized and characterized bulk samples of nearly pure sp3-hybridized ultrahard amorphous carbon,core-shell nanocrystals with high Néel temperatures,as well as large-sized single crystals of lower-mantle minerals.The developed LVP techniques presented here could enable the exploration of the chemical and physical properties of novel materials and Earth’s interior.展开更多
Negative Poisson ratio(NPR)steel is a new material with high strength and toughness.This study conducted tensile tests at elevated temperatures to investigate the mechanical properties of NPR steel at high temperature...Negative Poisson ratio(NPR)steel is a new material with high strength and toughness.This study conducted tensile tests at elevated temperatures to investigate the mechanical properties of NPR steel at high temperatures.The stress−strain curve,ultimate strength,yield strength,modulus of elasticity,elongation after fracture,and percentage reduction of area of NPR steel bars were measured at 9 different temperatures ranging from 20 to 800℃.The experimental results indicate that high-temperature environments significantly affect the mechanical properties of NPR steel.However,compared to other types of steel,NPR steel exhibits better resistance to deformation.When the test temperature is below 700℃,NPR steel exhibits a ductile fracture characteristic,while at 800℃,it exhibits a brittle fracture characteristic.Finally,based on the experimental findings,a constitutive model suitable for NPR steel at high temperatures is proposed.展开更多
Summer high temperatures have severely impaired the growth of herbaceous peony(Paeonia lactiflora Pall.)in East China.While compound fertilizer application enhances soil fertility and promotes plant growth,its efficac...Summer high temperatures have severely impaired the growth of herbaceous peony(Paeonia lactiflora Pall.)in East China.While compound fertilizer application enhances soil fertility and promotes plant growth,its efficacy in maintaining optimal plant performance under summer heat stress remains poorly understood.This study investigated the effects of compound fertilizer application on herbaceous peony growth during summer thermal stress.Results demonstrated that compound fertilizer supplementation significantly improved plant growth under elevated temperatures,manifesting enhanced phenotypic characteristics,elevated antioxidant enzyme activities,and increased nutrient accumulation.Compared to untreated controls,fertilized plants exhibited three key responses:(1)increased chlorophyll content coupled with reduced relative conductivity,malondialdehyde levels,and reactive oxygen species(ROS)accumulation;(2)upregulated activities of four critical antioxidant enzymes and augmented nitrogen,phosphorus,and potassium assimilation,collectively enhancing photosynthetic efficiency;and(3)stimulated expression of chlorophyll biosynthesis-related genes alongside suppressed transcription of chlorophyll degradation-associated genes.These findings establish a theoretical framework for optimizing compound fertilizer strategies to mitigate summer heat stress in herbaceous peony cultivation across East China.展开更多
Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems.Herein,we report a novel solution-processed core-shell structured poly-imide(PI)nanoc...Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems.Herein,we report a novel solution-processed core-shell structured poly-imide(PI)nanocomposite with moderate dielectric constant HfO_(2)core and wide-bandgap Al_(2)O_(3)shell,ef-fectively addressing the typical trade-off between dielectric constant and breakdown strength in dielectric nanocomposites predominant at elevated temperatures.The formation of improved dielectrically match-ing interfaces by the rationally designed dielectric constant gradient from core-shell-matrix remarkably mitigates the distortion of the electric field around the interfaces,resulting in a high breakdown strength.Wide band gap Al_(2)O_(3)shell also introduces deeper traps to impede the conduction loss.The validity of Al_(2)O_(3)shell has been proved via experiments and simulations.Accordingly,HfO_(2)@Al_(2)O_(3)/PI nanocompos-ite exhibits an excellent charge-discharge efficiency of 91.7%at 300 MV/m and a maximum discharged energy density of 2.94 J/cm^(3)at 150℃,demonstrating its potential for high-temperature energy storage.展开更多
基金Project(51879135)supported by the Taishan Scholars Program,ChinaProject(52309130)supported by the National Natural Science Foundation of China+1 种基金Project(SKLGME023003)supported by the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering Safety,ChinaProject(2022AH051754)supported by the Natural Science Research Project of Anhui Universities,China。
文摘The effect of real-time high temperature and thermal treatment on the mechanical characteristics and crack evolution of granite with different grain sizes(i.e.,0.5 mm,0.7 mm and 1.0 mm)is investigated by numerical simulation employing a grain-based model,and the impact of initial cracks on thermal-induced strengthening is also examined by integrating random cracks within the model before tests.The results revealed that thermal stress,induced by the mismatch in thermal expansion coefficient between various minerals,is the primary distinction between rock specimens in real-time high temperature and thermal treatment.With increasing temperature,the thermal stress gradually accumulates in quartz minerals under real-time high temperature but releases after thermal treatment.The high local contact force significantly affects the peak stress and crack evolution.Uniaxial compression simulation results demonstrate that progressive accumulation of thermal stress induces degradation in macroscopic peak strength and increase of microcrack density.The grain size controls the ratio of intergranular contacts to intragranular contacts,and leads to an increase in strong contact number in the intragrain and a decrease in strong contact number in the intergrain.The strengthening of uniaxial compression strength in the experiment can be well simulated by controlling the number of pre-existing initial cracks in the numerical model.Our conclusions are beneficial to a better understanding of the underlying mechanisms of thermal damage and thermal strengthening of granite for deep geological engineering.
基金financially supported by the National Natural Science Foundation of China (32071978)the National Key Research and Development Program of China (2022YFD2300901 and 2022YFD2300905)。
文摘High temperature stress (HT) significantly reduces maize yield by impairing starch accumulation in kernels.However,the mechanism by which HT affects starch synthesis remains controversial-whether through reduced assimilate supply or direct inhibition on kernel metabolism.To clarify these mechanisms,a heat-sensitive maize hybrid,Xianyu 335 (XY),was exposed to 30℃/20℃ (maximum/minimum temperature,control) and 40℃/30℃ for seven consecutive days during the seed setting stage.Synchronous pollination (SP),apical pollination (AP),and shading treatments were applied to manipulate the inherent source–sink ratio in maize plants.Results showed that apical kernel weight decreased by 11.9%under 40℃ in the SP treatment.The ^(13)C content,starch accumulation,and cell-wall invertase (CWIN) activity also declined by 15.9,36.7,and 16.4%,respectively,under HT.In the shading treatment,40℃/30℃ caused even greater reductions in^(13)C content,starch accumulation,and CWIN activity due to diminished assimilate supply.Conversely,in the AP treatment,starch content and CWIN activity increased by 22.0 and 18.5%,respectively,under 40℃/30℃,resulting in kernel weight and ^(13)C content similar to those in SP and shading treatments regardless of temperature.Consistent with apical kernels under AP,HT did not negatively affect middle kernels in either SP or shading treatments,as kernel weight and starch content remained unchanged under HT.Although all kernels were exposed to the same HT or control environment,their responses varied a lot.The impaired starch synthesis in apical kernels under HT was rescued by increasing carbon supply via AP treatment.The contrasting performance among middle kernels,apical kernels under AP,and apical kernels under SP or shading indicates that reduced carbon supply is a critical factor underlying inhibited starch accumulation.Our findings provide a theoretical basis for further understanding kernel abortion under HT.
基金funded by the Earmarked Fund for China Agriculture Research System,grant number CARS-01-33.
文摘Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on these characteristics.This study aimed to characterize spikelet filling in early-season rice and identify the key factors contributing to its improvement.Field experiments were conducted over two years(2021 and 2022)to mainly investigate the proportions of fully-filled,partially-filled,and empty spikelets,along with the biomass-fertilized spikelet ratio and harvest index,in 11 early-season rice varieties.The results revealed significant varietal variation in spikelet filling,with the proportion of fully-filled spikelets ranging from 60.6%to 81.1%in 2021 and from 66.3%to 79.2%in 2022.Among the 11 varieties,Liangyou 42,Lingliangyou 942,and Liangyou 287 exhibited relatively superior performance in spikelet filling.Linear regression revealed that,although a significant negative relationship existed between the proportion of fully-filled spikelets and both partially-filled and empty spikelets,the relationship with partially-filled spikelets was stronger.Additionally,the proportion of fully-filled spikelets showed a significant positive relationship with the harvest index but not with the biomass-fertilized spikelet ratio.These findings indicate that increasing the harvest index and reducing the occurrence of partially-filled grains are essential strategies for improving spikelet filling in early-season rice.
基金project was supported by the Fund of State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China)(No.SKLDOG2024-ZYRC-06)Key Program of National Natural Science Foundation of China(52130401)+1 种基金National Natural Science Foundation of China(52104055,52374058)Shandong Provincial Natural Science Foundation,China(ZR2021ME171,ZR2024YQ043)。
文摘CO_(2)flooding enhanced oil recovery(CO_(2)-EOR)represents a significant technology in the low permeability reservoir.With the fractures and heterogeneity in low permeability reservoirs,CO_(2)-EOR is susceptible to pessimistic gas channeling.Consequently,there is a need to develop conformance control materials that can be used in CO_(2)-EOR.Herein,to address the challenges of low strength and poor stability of polymer gel in high temperature and low permeability reservoirs,a new organic/metal ion composite crosslinking polymer gel(AR-Gel)is reported,which is formed by low hydrolysis and medium to high molecular weight polymer(CX-305),organic crosslinking agent(phenolic resin),and aluminium citrate(AI(Ⅲ)).The crosslinking of AI(Ⅲ)with carboxyl group and organic/metal ion double crosslinking can construct a more complex and stable polymer gel structure on the basis of traditional chemical crosslinking,to cope with the harsh conditions such as high temperature.The structure-activity relationship of AR-Gel was revealed by rheology behavior and micro-morphology.The applicability of AR-Gel in reservoir was investigated,as was its strength and stability in supercritical CO_(2).The anti-gas channeling and enhanced oil recovery of AR-Gel were investigated using low permeability fractured cores,and the field process parameters were provided.The gel can be used to meet supercritical CO_(2)reservoirs at 110℃and 20,000 mg/L salinity,with long-term stability over 60 days.The plugging rate of AR-Gel for fractured co re was 97%,with subsequent CO_(2)flooding re sulting in an enhanced oil recovery by 34.5%.ARGel can effectively control CO_(2)gas channeling and enhanced oil recovery.It offers a new material with high strength and temperature resistance,which is particularly beneficial in the CO_(2)flooding for the conformance control of oil field.
基金funding support from the National Natural Science Foundation of China(Grant No.52274082)the Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology(Grant No.JXUSTQJBJ2020003)the Innovation Fund Designated for Graduate Students of Jiangxi Province(Grant No.YC2023-B215).
文摘The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles.
基金supported by the National Natural Science Foundation of China(52172265)Excellent Youth Science Foundation of Hunan Province(2022JJ20067)+1 种基金The Science and Technology Innovation Program of Hunan Province(2022RC1074)Central South University Innovation-Driven Research Program(2023CXQD010).
文摘Polymer dielectrics possessing excellent electrical insulation and high thermal conductivity are pivotal for dielectric capacitors at elevated temperatures.However,the integration of electrical insulation and thermal conductivity in polymers remains a challenge.In this work,we present a feasible strategy to integrate high electrical insulation and high thermal conductivity by bonding carbon quantum dots(CQDs)with the diamine monomer of polyetherimide(PEI).The CQDs with Coulomb blockade effect serve as traps for the migrating of electrons in the dielectrics,while the bonding networks formed by CQDs and PEI further deepen the traps and augment trap density.As a result,the hybrid dielectrics(PEI-NH_(2)-CQDs)exhibit nearly an order of magnitude higher electrical resistivity than that of pure PEI,leading to an 80%increase in discharge energy density with an energy efficiency of 90%at 200℃ compared to pure counterpart.Additionally,this all-organic dielectric achieves a significantly increased thermal conductivity of 0.65 W m^(-1) K^(-1) compared to 0.26 W m^(-1) K^(-1) of PEI,which supports its cyclic stability at elevated temperatures.We also demonstrate the kilogram-scale production of CQDs,synthesizing over 8 kg in a single batch,paving the way for large-scale production of reliable PEI-NH_(2)-CQDs dielectrics.
基金supported by NSFC(Grant No.52202265,52302004,52472010,62434010)the Taishan Scholars Program of Shandong Province(tsqn202306330)+1 种基金Shenzhen Science and Technology Program(JCYJ20230807094009018)Xiaomi Young Talents Program(2023XM06).
文摘Gallium nitride(GaN)single crystal with prominent electron mobility and heat resistance have great potential in the high temperature integrate electric power systems.However,the sluggish charge storage kinetics and inadequate energy densities are bottlenecks to its practical application.Herein,the self-supported GaN/Mn_(3)O_(4) integrated electrode is developed for both energy harvesting and storage under the high temperature environment.The experimental and theoretical calculations results reveal that such integrated structures with Mn-N heterointerface bring abundant active sites and reconstruct low-energy barrier channels for efficient charge transferring,reasonably optimizing the ions adsorption ability and strengthening the structural stability.Consequently,the assembled GaN based supercapacitors deliver the power density of 34.0 mW cm^(-2) with capacitance retention of 81.3%after 10000 cycles at 130℃.This work innovatively correlates the centimeter scale GaN single crystal with ideal theoretical capacity Mn_(3)O_(4) and provides an effective avenue for the follow-up energy storage applications of the wide bandgap semiconductor.
基金supported by the Chongqing Natural Science Foundation of Chongqing,China(No.CSTB2022NSCQ-MSX0333)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202401205)+1 种基金Chongqing Three Gorges University Graduate Research and Innovation Project Funding(No.YJSKY24045)Chongqing Engineering Research Center of Disaster Prevention&Control for Banks and Structures in Three Gorges Reservoir Area(No.SXAPGC24YB14,No.SXAPGC24YB03,No.SXAPGC24YB12)。
文摘Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production efficiency of shale oil resources.Effectively stimulating oil shale reservoirs remains a challenging and active research topic.This investigation employed shale specimens obtained from the Longmaxi Formation.Scanning electron microscopy,fluid injection experiments,and fluid-structure interaction simulations were used to comprehensively analyze structural changes and fluid flow behavior under high temperatures from microscopic to macroscopic scales.Experimental results indicate that the temperature has little effect on the structure and permeability of shale before 300℃.However,there are two threshold temperatures within the range of 300 to 600℃that have significant effects on the structure and permeability of oil shale.The first threshold temperature is between 300 and 400℃,which causes the oil shale porosity,pore-fracture ratio,and permeability begin to increase.This is manifested by the decrease in micropores and mesopores,the increase in macropores,and the formation of a large number of isolated pores and fissures within the shale.The permeability increases but not significantly.The second threshold temperature is between 500 and 600℃,which increases the permeability of oil shale significantly.During this stage,micropores and mesopores are further reduced,and macropores are significantly enlarged.A large number of connected and penetrated pores and fissures are formed.More numerous and thicker streamlines appear inside the oil shale.The experimental results demonstrate that high temperatures significantly alter the microstructure and permeability of oil shale.At the same time,the experimental results can provide a reference for the research of in-situ heating techniques in oil shale reservoir transformation.
基金supported by the National Natural Science Foundation of China(Nos.52201207 and 52271169)the Fundamental Research Funds for the Central University(No.3072024LJ1002).
文摘The active development of space industry necessitates the cre-ation of novel materials with unique properties,including shape memory alloys(SMAs).The development of ultra-high temperature SMAs(UHTSMAs)with operating temperatures above 400℃is a significant challenge[1-3].It is known that reversible thermoelas-tic martensitic transformation(MT)is the basis for shape mem-ory behavior[4].Currently,there are several systems in which MT temperatures meet the above requirements,for example,RuNb[5],HfPd[6],TiPd[7].
基金supported by the National Natural Science Foundation of China(Grant Nos.52205140,52175129)the Outstanding Youth Foundation of Hunan Province(Grant No.2023JJ20041)the Science and Technology Innovation Program of Hunan Province(2023RC3241).
文摘This work investigated the anisotropy tensile properties of Inconel 625 alloy fabricated by laser powder bed fusion (LPBF) under various tests temperature, focusing the anisotropy evolution during the high temperature. The microstructure contained columnar grains with (111) texture in the vertical plane (90° sample), while a large equiaxed grain with (100) texture was produced in the horizontal plane (0° sample). As for 45° sample, a large number of equiaxed grains and a few columnar grains with (111) texture can be observed. The sample produced at a 0° orientation demonstrates the highest tensile strength, whereas the 90° sample exhibits the greatest elongation. Conversely, the 45° sample displays the least favorable overall performance. As the tests temperature increased from room temperature to 600℃, the anisotropy rate of ultimate tensile strength, yield strength and ductility between 0° and 45° samples, decreased from 8.98 to 6.96%, 2.36 to 1.28%, 19.93 to 12.23%, as well as between 0° and 90° samples decreased from 4.87 to 4.03%, 11.88 to 7.21% and 14.11 to 6.89%, respectively, because of the recovery of oriented columnar grains.
基金supported by the National Key R&D Program of China(2024YFB4106400)National Natural Science Foundation of China(22209200,52302331)。
文摘Electrocatalytic reduction of carbon dioxide(CO_(2))to carbon monoxide(CO)is an effective strategy to achieve carbon neutrality.High selective and low-cost catalysts for the electrocatalytic reduction of CO_(2)have received increasing attention.In contrast to the conventional tube furnace method,the high-temperature shock(HTS)method enables ultra-fast thermal processing,superior atomic efficiency,and a streamlined synthesis protocol,offering a simplified method for the preparation of high-performance single-atom catalysts(SACs).The reports have shown that nickel-based SACs can be synthesized quickly and conveniently using the HTS method,making their application in CO_(2)reduction reactions(CO_(2)RR)a viable and promising avenue for further exploration.In this study,the effect of heating temperature,metal loading and different nitrogen(N)sources on the catalyst morphology,coordination environment and electrocatalytic performance were investigated.Under optimal conditions,0.05Ni-DCD-C-1050 showed excellent performance in reducing CO_(2)to CO,with CO selectivity close to 100%(−0.7 to−1.0 V vs RHE)and current density as high as 130 mA/cm^(2)(−1.1 V vs RHE)in a flow cell under alkaline environment.
基金supported by the National Natural Science Foundation of China(Grant No.52207031)the National Key R&D Program of China(Grant No.2020YFA0710500)。
文摘High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications,but the trade-off between energy density and temperature stability remains fundamentally challenging.Here,we report a general material design strategy to enhance energy storage performance at high temperatures by crosslinking a polar polymer and a high glass-transition temperature polymer as a crosslinked binary blend.Such crosslinked binary polymers display a temperature-insensitive and high energy density behavior of about6.2~8.5 J cm^(-3) up to 110℃,showing a significant enhancement in thermal resistant properties and consequently outperforming most of the other ferroelectric polymers.Further microstructural investigations reveal that the improved thermal stability stems from the confinement effect on conformational motion of the crosslinking network,which is evidenced by the increased rigid amorphous fraction and steady intermolecular distance of amorphous regions from temperature-dependent X-ray diffraction results.Our findings provide a general and straightforward strategy to attain temperature-stable,high-energy-density polymer-based dielectrics for energy storage capacitors.
基金co-supported by the financial support from the Fundamental Research Funds for the Central Universities,China(Nos.YWF-23-L-1012,YWF-22-L-1017)the National Natural Science Foundation of China(No.52005020)。
文摘The performance of welded Ni-based superalloys at high temperatures is essential to be evaluated due to their particular service environment for aero-engines and high-speed aircrafts.The tensile properties and related microstructural evolutions such as the carbide precipitate and grain of a laser-welded Ni-based alloy were experimentally and numerically investigated at different temperatures(20,300,500,800℃).The results show that at room temperature,the strength of the Base Material(BM)was slightly smaller,with a difference of less than 1%,than the Welded Material(WM),which can be attributed to the more uniformly distributed needle-shaped carbide precipitates in the WM than those nonuniformly coarser spherical ones in the BM.While at 300℃ and 500℃,the strength of WM decreased more obviously compared with that of BM due to the more apparent growth of grain:13.52%loss in yield strength in WM alloys as compared with BM alloys at 300℃,and 16.57% at 500℃.At 800℃,the strength of BM and WM both decreased to a similar level due to Dynamic Recrystallization(DRX).However,a much higher elongation was observed for the BM than WM(less than 50%of BM),which can be attributed to the enhanced dislocation accumulation capability of the large spherical carbides along grain boundaries on the fracture surface in BM.Furthermore,a unified model considering the welding effects on both microstructures(dislocation,carbides,and grain)and mechanical properties evolutions at different temperatures was developed and validated.Based on this model,the key temperature ranges(20–600℃)where apparent weakening of strength and uniform plasticity occurs for welded structures were identified,providing a direct guidance for potential structure and process design.
基金supported by Natural Science Foundation of China(Grant/Award 52077171).
文摘The interface pressure between cables and accessories plays a crucial role in the long-term reliable operation of cable systems.However,the change in interface pressure at high temperature and its influencing mechanism are still inconclusive.In this study,the changes of interface pressure at high temperature mainly caused by three influencing factors were investigated through theoretical analysis and experimental measurements.The results revealed that the thermal expansion effect will result in a decrease in interface pressure,while the Gough-Joule effect of rubber materials at high temperature will lead to an increase in interface pressure as the temperature rises.Additionally,the stress relaxation effect of rubber-like materials at high temperature will accelerate the decline in interface pressure.Finally,a calculation method for interface pressure based on the comprehensive effect of these factors is proposed.The results showed that the interface pressure increases as the temperature rises,indicating that the Gough-Joule effect of rubber materials dominates the change in interface pressure.The error between the theoretical calculation and actual measurement of interface pressure was<5%.Therefore,this method can feasibly be used to evaluate the interface pressure in the medium-voltage(MV)and even high-voltage(HV)integral prefabricated cable accessories as the temperature changes.
基金supported by the National Key Research and Development Program of China(2022YFB3803400)。
文摘High-nickel cathode LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)could enable lithium-ion batteries(LIBs)with high energy density.However,excessive decomposition of the electrolyte would happen in the high operating voltage range.In addition,the utilization of flammable organic solvents would increase safety risks in the high temperature environment.Herein,an electrolyte consisting of flame-retardant solvents with lower highest occupied molecular orbital(HOMO)level and LiDFOB salt is proposed to address above two issues.As a result,a thin and robust cathode-electrolyte interface containing rich LiF and Li-B-O compounds is formed on the cathode to effectively suppress electrolyte decomposition in the high operating voltage.The NCM811||Li cell paired with this designed electrolyte possesses a capacity retention of 72%after 300 cycles at 55℃.This work provides insights into developing electrolyte for stable high-nickel cathode operated in the high temperature.
基金support by National Natural Science Foundation of China(22379166)Natural Science Foundation for Distinguished Young Scholars of Hunan Province(2022JJ10089)Central South University Innovation-Driven Research Programme(2023CXQD034).
文摘Within the framework of carbon neutrality,lithium-ion batteries(LIBs)are progressively booming along with the growing utilization of green and clean energy.However,the extensive application of LIBs with limited lifespan has brought about a significant recycling dilemma.The traditional hydrometallurgical or pyrometallurgical strategies are not capable to maximize the output value of spent LIBs and minimize the potential environmental hazards.Herein,to alternate the tedious and polluting treatment processes,we propose a high-temperature molten-salt strategy to directly regenerate spent cathodes of LIBs,which can also overcome the barrier of the incomplete defects'restoration with previous low-temperature molten salts.The high-energy and stable medium environment ensures a more thorough and efficient relithiation reaction,and simultaneously provides sufficient driving force for atomic rearrangement and grains secondary growth.In consequence,the regenerated ternary cathode(R-NCM)exhibits significantly enhanced structural stability that effectively suppresses the occurrence of cracks and harmful side reactions.The R-NCM delivers excellent cycling stability,retaining 81.2%of its capacity after 200 cycles at 1 C.This technique further optimizes the traditional eutectic molten-salt approach,broadening its applicability and improving regenerated cathode performance across a wider range of conditions.
基金supported by the National Key Research and Development Program of China(2022YFB3706600 and 2023YFA1406200)the National Natural Science Founda-tion of China(42272041,52302043,12304015,41902034,and 12011530063)+1 种基金the Jilin University High-level Innovation Team Foundation,China(2021TD-05)the National Major Science Facility Synergetic Extreme Condition User Facility Achievement Transformation Platform Construction(2021FGWCXNLJSKJ01).
文摘Ultrahigh pressure generation at high temperatures is technologically challenging for large sample volumes.In this study,we successfully generated pressures of 37.3-40.4 GPa at 1900-2100 K in a Walker-type large-volume press(LVP).Expansion of the pressure range at high temperatures was achieved by adapting newly designed ZK01F tungsten carbide(WC)anvils with tapered surfaces and using cell assemblies with an^(-1) mm^(3) sample volume and hard materials,as well as by applying certain adjustments to the apparatus.The pressure efficiencies of the different types of WC anvils and cell assemblies were also studied.Using the above-mentioned techniques,we successfully synthesized and characterized bulk samples of nearly pure sp3-hybridized ultrahard amorphous carbon,core-shell nanocrystals with high Néel temperatures,as well as large-sized single crystals of lower-mantle minerals.The developed LVP techniques presented here could enable the exploration of the chemical and physical properties of novel materials and Earth’s interior.
基金Projects(41702320,52104125)supported by the National Natural Science Foundation of ChinaProject(ZR2021MD005)+2 种基金supported by the Natural Science Foundation of Shandong Province,ChinaProject(TMduracon2022002)supported by the Engineering Research Center of Marine Environmental Concrete Technology,Ministry of Education,China。
文摘Negative Poisson ratio(NPR)steel is a new material with high strength and toughness.This study conducted tensile tests at elevated temperatures to investigate the mechanical properties of NPR steel at high temperatures.The stress−strain curve,ultimate strength,yield strength,modulus of elasticity,elongation after fracture,and percentage reduction of area of NPR steel bars were measured at 9 different temperatures ranging from 20 to 800℃.The experimental results indicate that high-temperature environments significantly affect the mechanical properties of NPR steel.However,compared to other types of steel,NPR steel exhibits better resistance to deformation.When the test temperature is below 700℃,NPR steel exhibits a ductile fracture characteristic,while at 800℃,it exhibits a brittle fracture characteristic.Finally,based on the experimental findings,a constitutive model suitable for NPR steel at high temperatures is proposed.
基金supported by the Jiangsu Province Seed Industry Revitalization Unveiled Project(JBGS(2021)020)Forestry Science,Technology Innovation and Promotion Project of Jiangsu Province(LYKJ[2021]01)National Forest and Grass Science and Technology Innovation and Development Research Project(2023132012).
文摘Summer high temperatures have severely impaired the growth of herbaceous peony(Paeonia lactiflora Pall.)in East China.While compound fertilizer application enhances soil fertility and promotes plant growth,its efficacy in maintaining optimal plant performance under summer heat stress remains poorly understood.This study investigated the effects of compound fertilizer application on herbaceous peony growth during summer thermal stress.Results demonstrated that compound fertilizer supplementation significantly improved plant growth under elevated temperatures,manifesting enhanced phenotypic characteristics,elevated antioxidant enzyme activities,and increased nutrient accumulation.Compared to untreated controls,fertilized plants exhibited three key responses:(1)increased chlorophyll content coupled with reduced relative conductivity,malondialdehyde levels,and reactive oxygen species(ROS)accumulation;(2)upregulated activities of four critical antioxidant enzymes and augmented nitrogen,phosphorus,and potassium assimilation,collectively enhancing photosynthetic efficiency;and(3)stimulated expression of chlorophyll biosynthesis-related genes alongside suppressed transcription of chlorophyll degradation-associated genes.These findings establish a theoretical framework for optimizing compound fertilizer strategies to mitigate summer heat stress in herbaceous peony cultivation across East China.
基金supported by the National Natu-ral Science Foundation of China(Nos.52107232 and 52377026)China Postdoctoral Science Foundation(No.2021M702563)+2 种基金State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE22312)Taishan Scholars and Young Experts Program of Shan-dong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)and Fundamental Research Funds for the Central Universities(No.xzy012024004).
文摘Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems.Herein,we report a novel solution-processed core-shell structured poly-imide(PI)nanocomposite with moderate dielectric constant HfO_(2)core and wide-bandgap Al_(2)O_(3)shell,ef-fectively addressing the typical trade-off between dielectric constant and breakdown strength in dielectric nanocomposites predominant at elevated temperatures.The formation of improved dielectrically match-ing interfaces by the rationally designed dielectric constant gradient from core-shell-matrix remarkably mitigates the distortion of the electric field around the interfaces,resulting in a high breakdown strength.Wide band gap Al_(2)O_(3)shell also introduces deeper traps to impede the conduction loss.The validity of Al_(2)O_(3)shell has been proved via experiments and simulations.Accordingly,HfO_(2)@Al_(2)O_(3)/PI nanocompos-ite exhibits an excellent charge-discharge efficiency of 91.7%at 300 MV/m and a maximum discharged energy density of 2.94 J/cm^(3)at 150℃,demonstrating its potential for high-temperature energy storage.
