Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sen...Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I, the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different front that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I. For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.展开更多
High-temperature microwave absorbing materials(MAMs)and structures are increasingly appealing due to their critical role in stealth applications under harsh environments.However,the impedance mismatch caused by increa...High-temperature microwave absorbing materials(MAMs)and structures are increasingly appealing due to their critical role in stealth applications under harsh environments.However,the impedance mismatch caused by increased conduction loss often leads to a significant decline in electromagnetic wave absorp-tion(EMWA)performance at elevated temperatures,which severely restricts their practical application.In this study,we propose a novel approach for efficient electromagnetic wave absorption across a wide temperature range using reduced graphene oxide(RGO)/epoxy resin(EP)metacomposites that integrate both electromagnetic parameters and metamaterial design concepts.Due to the discrete distribution of the units,electromagnetic waves can more easily penetrate the interior of materials,thereby exhibiting stable microwave absorption(MA)performance and impedance-matching characteristics suitable across a wide temperature range.Consequently,exceptional MA properties can be achieved within the tem-perature range from 298 to 473 K.Furthermore,by carefully controlling the structural parameters in RGO metacomposites,both the resonant frequency and effective absorption bandwidth(EAB)can be optimized based on precise manipulation of equivalent electromagnetic parameters.This study not only provides an effective approach for the rational design of MA performance but also offers novel insights into achieving super metamaterials with outstanding performance across a wide temperature spectrum.展开更多
Low temperature(LT)in spring has become one of the principal abiotic stresses that restrict the growth and development of wheat.Diverse analyses were performed to investigate the mechanism underlying the response of w...Low temperature(LT)in spring has become one of the principal abiotic stresses that restrict the growth and development of wheat.Diverse analyses were performed to investigate the mechanism underlying the response of wheat grain development to LT stress during booting.These included morphological observation,measurements of starch synthase activity,and determination of amylose and amylopectin content of wheat grain after exposure to treatment with LT during booting.Additionally,proteomic analysis was performed using tandem mass tags(TMT).Results showed that the plumpness of wheat grains decreased after LT stress.Moreover,the activities of sucrose synthase(SuS,EC 2.4.1.13)and ADP-glucose pyrophosphorylase(AGPase,EC 2.7.7.27)exhibited a significant reduction,leading to a significant reduction in the contents of amylose and amylopectin.A total of 509 differentially expressed proteins(DEPs)were identified by proteomics analysis.The Gene Ontology(GO)enrichment analysis showed that the protein difference multiple in the nutritional repository activity was the largest among the molecular functions,and the up-regulated seed storage protein(ssP)played an active role in the response of grains to LT stress and subsequent damage.The Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis showed that LT stress reduced the expression of DEPs such as sucrose phosphate synthase(SPS),glucose-1-phosphate adenylyltransferase(glgC),andβ-fructofuranosidase(FFase)in sucrose and starch metabolic pathways,thus affecting the synthesis of grain starch.In addition,many heat shock proteins(HsPs)were found in the protein processing in endoplasmic reticulum pathways,which can resist some damage caused by LT stress.These findings provide a new theoretical foundation for elucidating the underlying mechanism governing wheat yield developmentafterexposuretoLTstress inspring.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
The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and...The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains limited.In this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal forest.The estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario datasets.The sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime temperature.The LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN model.By incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is achieved.Furthermore,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study area.The simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate scenarios.This study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.展开更多
The dissolved organic matter(DOM)with high mobility and reactivity plays a crucial role in soil.In this study,the characteristics and phytotoxicity ofDOMreleased fromthe hydrochars prepared from different feedstocks(c...The dissolved organic matter(DOM)with high mobility and reactivity plays a crucial role in soil.In this study,the characteristics and phytotoxicity ofDOMreleased fromthe hydrochars prepared from different feedstocks(cowmanure,corn stalk and Myriophyllum aquaticum)under three hydrothermal carbonization(HTC)temperatures(180,200 and 220°C)were evaluated.The results showed that the hydrochars had high dissolved organic carbon content(20.15 to 37.65 mg/g)and its content showed a gradual reduction as HTC temperature increased.Three fluorescent components including mixed substance of fulvic acid-like and humic acid-like substances(C1,30.92%-58.32%),UVA humic acid-like substance(C2,25.27%-29.94%)and protein-like substance(C3,11.74%-41.92%)were identified in hydrochar DOM by excitation emission matrix spectra coupled with parallel factor analysis.High HTC temperature increased the relative proportion of aromatic substances(C1+C2)and humification degree of hydrochar DOM from cow manure,while it presented adverse effects on the hydrochar DOM from corn stalk and Myriophyllum.aquaticum.The principal component analysis suggested that feedstock type and HTC temperature posed significant effects on the characteristics of hydrochar DOM.Additionally,seed germination test of all hydrochar DOM demonstrated that the root length was reduced by 8.88%-26.43%in contrast with control,and the germination index values were 73.57%-91.12%.These findings provided new insights into the potential environmental effects for hydrochar application in soil.展开更多
The global climate change and ocean acidification brought about by the anthropogenic release of carbon dioxide gas into the air is considered one of the greatest problems facing marine life.In this research,the intera...The global climate change and ocean acidification brought about by the anthropogenic release of carbon dioxide gas into the air is considered one of the greatest problems facing marine life.In this research,the interactions between two species of fish(the gold mollies and tiger barb)were investigated under two different environmental conditions,an elevated temperature of 28°C and a low pH of 5 and a normal pH of 7 and a normal temperature of 24°C.The mollies at pH 7 and a temperature of 24°C exhibited scary interactions with the tiger barb.They were scared and ran fast away from the tiger barb.At the same time,the mollies at pH 5 and a temperature of 28°C interacted normally as though both species were one species showing behavioral changes due to these two stressors(pH 5 and elevated temperature 28°C).This could be the only research that has addressed how the kinematics and swimming interactions of two species of fish changed in response to elevated temperature and low pH.展开更多
A metal-sensitive diaphragm fiber optic pressure sensor with temperature compensation is developed for pressure monitoring in high-temperature environments,such as engine fuel systems,oil and gas wells,and aviation hy...A metal-sensitive diaphragm fiber optic pressure sensor with temperature compensation is developed for pressure monitoring in high-temperature environments,such as engine fuel systems,oil and gas wells,and aviation hydraulic systems.The sensor combines a metal-sensitive diaphragm and a sapphire wafer to form a temperature-pressure dual Fabry-Perot(FP)interference cavity.A cross-correlation signal demodulation algorithm and a temperature decoupling method are utilized to reduce the influence of temperature crosstalk on pressure measurement.Experimental results show that the maximum nonlinear error of the sensor pressure measurement is 0.75%full scale(FS)and 0.99%FS at room temperature and 300°C,respectively,in a pressure range of 0−10 MPa and 0−1.5 MPa.The sensor’s pressure measurement accuracy is 1.7%FS when using the temperature decoupling method.The sensor exhibits good static pressure characteristics,stability,and reliability,providing an effective solution for high-temperature pressure monitoring applications.展开更多
Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses.It has been widely applied to produce solanaceous and melon vegetables.Temperature is an important external...Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses.It has been widely applied to produce solanaceous and melon vegetables.Temperature is an important external factor affecting graft formation.However,the molecular mechanism by which external ambient temperature affects tomato graft formation remains unclear.In this study,we demonstrated that elevating ambient temperature during grafting to 35℃ for more than 24 h after grafting accelerated vascular reconnection.We generated self-or heterografted combinations between phyB1B2 and pif4 loss-of-function mutant and wild-type plants,and were mutants unresponsive to graft formation at elevated ambient temperature.In addition,elevated ambient temperature induced SlPIF4 expression during grafting.SlPIF4 directly binds the promoters of auxin biosynthesis genes SlYUCCAs and activates their expression.Further investigation revealed auxin accumulation in the graft junction under elevated ambient temperature.The results illuminate the mechanism by which the PHYB-PIF4-auxin module promotes tomato graft formation in response to elevated ambient temperature.展开更多
The ductile-to-brittle transition temperature(DBTT)of high strength steels can be optimized by tailoring microstructure and crystallographic orientation characteristics,where the start cooling temperature plays a key ...The ductile-to-brittle transition temperature(DBTT)of high strength steels can be optimized by tailoring microstructure and crystallographic orientation characteristics,where the start cooling temperature plays a key role.In this work,X70 steels with different start cooling temperatures were prepared through thermo-mechanical control process.The quasi-polygonal ferrite(QF),granular bainite(GB),bainitic ferrite(BF)and martensite-austenite constituents were formed at the start cooling temperatures of 780℃(C1),740℃(C2)and 700℃(C3).As start cooling temperature decreased,the amount of GB decreased,the microstructure of QF and BF increased.Microstructure characteristics of the three samples,such as high-angle grain boundaries(HAGBs),MA constituents and crystallographic orientation,also varied with the start cooling temperatures.C2 sample had the lowest DBTT value(−86℃)for its highest fraction of HAGBs,highest content of<110>oriented grains and lowest content of<001>oriented grains parallel to TD.The high density of{332}<113>and low density of rotated cube{001}<110>textures also contributed to the best impact toughness of C2 sample.In addition,a modified model was used in this paper to quantitatively predict the approximate DBTT value of steels.展开更多
[Objectives]To explore the effects of high soil temperature stress on microorganisms utilizing different carbon sources in the rhizosphere of pepper seedlings.[Methods]Using seedlings of the main pepper cultivar‘Reyi...[Objectives]To explore the effects of high soil temperature stress on microorganisms utilizing different carbon sources in the rhizosphere of pepper seedlings.[Methods]Using seedlings of the main pepper cultivar‘Reyin 1’as experimental materials,five soil temperature gradients(25,30,35,40,and 45℃)were established.After a 96 d cultivation,soil nutrient content and soil microbial functional diversity were measured to elucidate the impact of high soil temperature on the soil microenvironment.[Results]As soil temperature increased,the contents of total nitrogen,alkaline hydrolyzable nitrogen,available phosphorus,and rapidly available potassium generally showed a decreasing trend.However,under the 45℃ treatment,the contents of total nitrogen,available phosphorus,and rapidly available potassium were the highest among all treatments,although the alkaline hydrolyzable nitrogen content was significantly lower compared to the other treatments.BIOLOG analysis revealed that with increasing soil temperature,the average soil microbial absorbance value and the Shannon diversity index decreased significantly.In contrast,the Shannon evenness index and the Simpson dominance index showed no significant differences across the different temperature treatments.This indicates that as soil temperature rises,the carbon source utilization capacity of the soil microbial community decreases,leading to reduced overall carbon metabolic activity and microbial functional diversity,while the dominant microbial populations remained unchanged during this process.Principal component analysis further confirmed effective separation among the different temperature treatments,suggesting that high soil stress significantly altered the structure of the soil microbial community.[Conclusions]In practical production,appropriate measures should be taken to decrease soil temperature to create a favorable rhizosphere microenvironment and thereby promote crop growth.展开更多
Soft actuators endowed with self-sensing capability become highly sought after in recent years.Ti3C2Tx MXene is expected to be used in the development of self-sensing actuators due to its outstanding physical and chem...Soft actuators endowed with self-sensing capability become highly sought after in recent years.Ti3C2Tx MXene is expected to be used in the development of self-sensing actuators due to its outstanding physical and chemical properties.However,achieving precise deformation feedback of MXene-based actuators remains a challenge,as the resistance change of MXene is not only affected by deformation,but also by temperature,and the decoupling is difficult.Here,a composite ink with temperature self-compensation(0.00125%·°C^(−1) of temperature coefficient of resistance)is fabricated by combining MXene and graphite with opposite temperature coefficients of resistance.The composite ink can be written on a variety of substrates,including glass,cellulose paper,and various polymers.Based on this,an ink-cellulose/polymer composite actuator with self-sensing function is actualized.The actuator can achieve accurate real-time deformation feedback by monitoring the resistance signal of ink-cellulose layer,which shows a high linear sensitivity(gauge factor~14.5,coefficient of determination(R^(2))>0.99),thereby realizing the perception of touch behavior and distinguishing objects with different weights,softness,and roughness.Besides,a series of biomimetic devices and soft robots with programmable movements(rolling and self-sustained oscillating)are also demonstrated.The results offer new insights for the development of the self-sensing actuators.展开更多
This work attempts to optimize Graphene nanoplatelets(GPLs)distribution in the face sheet of sandwich plates to pursue the minimum thermal deflection and transverse shear stresses at interfaces.Thus,an Improved Legend...This work attempts to optimize Graphene nanoplatelets(GPLs)distribution in the face sheet of sandwich plates to pursue the minimum thermal deflection and transverse shear stresses at interfaces.Thus,an Improved Legendre Higher-order plate Theory combined with Isogeometric Analysis(ILHT-IGA)is,first,proposed to accurately predict thermomechanical behaviors of GPLs-reinforced sandwich plates,which can ensure the reliability of the optimized results.Then,an accelerated multi-objective optimization approach is proposed to optimize thermomechanical behaviors.The trained machine learning algorithm based on ILHT-IGA is employed as a surrogate model to accelerate the optimization process.Finally,X-shaped GPLs distribution can provide the maximum stiffness to resist thermal expansion.However,X-shaped GPLs distribution on face sheets will result in large difference of stiffnesses at adjacent surfaces of face sheets and core layer.Thus,transverse shear stresses at interfaces are obviously increased.To avoid a sudden increase of transverse shear stresses at interfaces,an alternative optimized GPLs distribution has been obtained,where GPLs gradually increase toward the upper and lower surfaces of face sheets and suddenly decrease near the surface of face sheets.Such distributions can effectively enhance the stiffness of sandwich plates to resist thermal expansion behaviors and decrease transverse shear stresses at interfaces.展开更多
Bismuth-doped antimony tungstate(Bi-doped Sb_(2)WO_(6))microspheres were synthesized via a novel hydrothermal synthesis approach.These microspheres were then used as active layers in gas sensors for the detection of c...Bismuth-doped antimony tungstate(Bi-doped Sb_(2)WO_(6))microspheres were synthesized via a novel hydrothermal synthesis approach.These microspheres were then used as active layers in gas sensors for the detection of carbon dioxide(CO_(2)),a significant greenhouse gas and a critical parameter for evaluating air quality.The incorporation of bismuth significantly enhances the gas-sensing performance of the Sb_(2)WO_(6)microspheres,with the 4%Bidoped sensing active layer achieving a remarkable response value of 15 when exposed to 200 ppm of CO_(2),outperforming the undoped Sb_(2)WO_(6).Furthermore,the selectivity of the 4%Bi-Sb_(2)WO_(6)sensor toward CO_(2)gas was enhanced relative to the Sb_(2)WO_(6)sensor.The fundamental mechanisms of gas sensing and the factors contributing to the improved CO_(2)response of 4%Bi-Sb_(2)WO_(6)micro spheres were investigated using density functional theory.Bi-doped Sb_(2)WO_(6)materials exhibit significant advantages in gas-sensing applications,including improved conductivity,enhanced gas adsorption capacity,increased reaction rates,good chemical stability,excellent selectivity,and the ability to adjust electron density.These characteristics enable Bi-doped Sb_(2)WO_(6)to demonstrate higher sensitivity and rapid response capabilities in gas sensors,making it suitable for practical applications.展开更多
In order to avoid poor machinability caused by excessive hardness under high-silicon conditions in the traditional free-cutting graphited steel,it is important to develop a suitable silicon-saving,aluminum-containing ...In order to avoid poor machinability caused by excessive hardness under high-silicon conditions in the traditional free-cutting graphited steel,it is important to develop a suitable silicon-saving,aluminum-containing free-cutting steel.This study investigated the microstructure and graphite precipitation behavior of Fe–0.58C–1.0Al(wt%)steels with varying silicon contents(0.55wt%–2.67wt%)after tempering at different temperatures(680℃,715℃).The tempering structure and the precipitation behavior of graphite and Fe_(3)C in Fe–0.58C–1.0Al steels were systematically studied by optical microscopy(OM),field emission scanning electron microscopy(FESEM),and electron microprobe analyzer(EPMA).The results showed that,at both tempering temperatures,the microstructure of 0.55wt%Si steel is ferrite+granular Fe_(3)C,and the microstructures of 1.38wt%–2.67wt%Si steels are ferrite+petaloid graphite+granular Fe_(3)C.With increasing Si content from 1.38wt%to 2.67wt%at constant tempering temperature,the number density of graphite particles increases,though their average size decreases.Meanwhile,the number density and average size of Fe_(3)C in experimental steels continuously decrease with the increase of Si content.For 0.55wt%Si steel without graphite precipitation,increasing tempering temperature promotes the accumulation and growth of Fe_(3)C.For 1.38wt%–2.67wt%Si steels with graphite precipitation,higher tempering temperature promotes graphite particles growth while accelerating the decomposition and refinement of Fe_(3)C.Furthermore,compared with the experimental steels containing 0.55wt%Si,1.38wt%Si,and 2.67wt%Si,the 1.89wt%Si steel exhibits significantly lower hardness.Especially,when tempered at 715℃,Fe–0.58C–1.0Al steel with 1.89wt%Si exhibits enhanced graphitization behavior and reduced hardness,which is nearly HV 20 lower than previously reported Fe–0.55C–2.33Si steel.展开更多
Temperature is well known as the major environmental factor that influences survival and growth of fish,which are poikilo-thermic animals.However,it is still unclear about the mechanism that underscores thermal-contro...Temperature is well known as the major environmental factor that influences survival and growth of fish,which are poikilo-thermic animals.However,it is still unclear about the mechanism that underscores thermal-controlled fish physiology,especially nutritional utilization and metabolism,which are vitally important in aquaculture.In the present study,juvenile turbot was force-fed with amino acid mixture and its postprandial absorption,nutrient sensing and metabolism under low(12,15℃),optimal(18℃)to high(21,24℃)temperatures were explored.Intestinal trypsin and lipase activity were highly sensitive to water temperature,and highest under optimal temperatures for turbot,whereas amylase remained constant.Selective groups of intestinal amino acid transporters were upregulated in cold temperatures,but the amino acid absorption capability was increased with rising temperature.The mechanistic target of rapamycin(mTOR)signaling pathway was most active at optimal temperature.Postprandial muscle protein deposition achieved maximum level under optimal temperature.Amino acid catabolic enzymes branched-chain aminotransferase and branched-chainα-keto acid dehydrogenase activities were increased with rising temperatures.High temperature increased significantly energy metabolism and stimulated cel-lular stress in liver.These findings highlight the critical role of temperature in modulating amino acid dynamics,metabolic processes and stress responses in juvenile turbot,providing valuable insights for optimizing aquaculture practices.展开更多
The properties and creation of optical centers in diamond are essential for applications in quantum technology.Here,we study the photoluminescence(PL)spectroscopy behavior at low temperatures of diamond subjected to e...The properties and creation of optical centers in diamond are essential for applications in quantum technology.Here,we study the photoluminescence(PL)spectroscopy behavior at low temperatures of diamond subjected to electron irradiation and annealing heat treatment.Through temperature variation testing,it was found that the NVcenter intensity of diamond with a nitrogen content of 150 ppm before treatment is insensitive to the experimental temperature,but significantly increases with decreasing temperature after treatment,showing sensitivity to temperature.In addition,the H3 center also shows an increasing trend with decreasing temperature.The results of annealing diamond with a nitrogen content of 730 ppm showed that even at a low temperature of 93 K,no NV^(-)centers were detected,but there were a large number of Ni-N related centers,especially NE8 centers.Our findings can promote a deeper understanding of the behavioral characteristics of HPHT-diamond optical centers in low-temperature environments.展开更多
The serrated flow behavior,known as the Portevin-Le Chatelier(PLC)effect,is commonly observed during high-temperature deformation.In this study,we report a serrated flow behavior in FeCoCrNiMo0.2 high-entropy alloy(HE...The serrated flow behavior,known as the Portevin-Le Chatelier(PLC)effect,is commonly observed during high-temperature deformation.In this study,we report a serrated flow behavior in FeCoCrNiMo0.2 high-entropy alloy(HEA),which is mediated by nano-twinning and phase transformation at cryogenic temperatures.During uniaxial tensile deformation at 77 K,the alloy exhibited the formation of high-density deformation nano-twinning,cross-twinning,stacking faults(SFs)and Lomer-Cottrell locks(L-C locks).Additionally,the lower stacking fault energy(SFE)at low temperatures promotes the formation of the 9R phase.The high-density twin boundaries effectively hinder dislocation movement,leading to the instability of plastic deformation and promoting the serrated flow behavior.Furthermore,the rapid and unstable transformation of the 9R phase contributes to the pronounced serrated flow behavior.Nano-twinning,SFs,cross-twinning,L-C locks and 9R phase collectively induce a dynamic Hall-Petch effect,enhancing the strength-ductility synergy and strain-hardening ability of deformed alloy at 77 K.Our work provides valuable insights into the mechanism of tensile deformation at cryogenic temperatures in single-phase FCC HEA.展开更多
Microstructures and properties of mortar using ammonium phosphate and potassium phosphate were tested and compared in this case.Moreover,two cementitious additions and two lightweight aggregates,including fly ash,redi...Microstructures and properties of mortar using ammonium phosphate and potassium phosphate were tested and compared in this case.Moreover,two cementitious additions and two lightweight aggregates,including fly ash,redispersible latex powder,ceramsite sand,and rubber powder,were respectively tried to be applied in magnesium ammonium phosphate cement mortar in order to modify the microstructures and properties.The experimental results show that potassium phosphate is not suitable for magnesium phosphate cement mortar for cold region construction purpose.Although fly ash can bring positive modification in the condition of normal temperature curing,it brings negative effects in the condition of sub-zero temperature curing.Either redispersible latex powder or ceramsite sand can improve the freeze-thaw cycling resistance of magnesium phosphate cement mortar in the conditions of low temperature coupled with freeze-thaw cycling,but only the ceramsite sand can improve both mechanical properties and freeze-thaw cycling resistance.The modification caused by ceramsite sand is mainly due to the exceptional bonding strength between hardened cement paste and the porous surface of ceramsite and the porous structure of ceramsite for the release of frost heave stress.展开更多
The degradation of Lithium-ion batteries(LIBs)during cycling is particularly exacerbated at low temperatures,which has a significant impact on the longevity of electric vehicles,energy storage systems,and consumer ele...The degradation of Lithium-ion batteries(LIBs)during cycling is particularly exacerbated at low temperatures,which has a significant impact on the longevity of electric vehicles,energy storage systems,and consumer electronics.A comprehensive understanding of the low-temperature aging mechanisms throughout the whole life cycle of LIBs is crucial.However,existing research is limited,which typically focuses on capacity degradation to 80%.To fill this gap,this paper conducts low-temperature cyclic aging tests at three different charging rates.The investigation employs differential voltage analysis,the distribution of relaxation times technique,and disassembly characterization to explore both thermodynamic degradation and kinetic degradation,alongside a correlation analysis of the factors influencing these degradation processes.The results reveal two distinct knee points in the capacity decline of LIBs during the whole life cycle,in contrast to prior studies identifying only one.Before the first knee point,the thickening of the SEI film dominates capacity loss,with higher charging rates accelerating the process.After the first knee point,the main degradation mechanisms shift to lithium plating and the fracture of the positive electrode active particles.These two aging factors become more pronounced with ongoing cycling,culminating in a second knee point in capacity decline.Notably,a novel finding demonstrates that after the second knee point,capacity degradation progresses faster at lower charging rates compared to medium rates.The reason is the fracture of graphite particles also becomes a critical contributor to the severe capacity degradation at lower charging rates.These insights will guide the designs of next-generation low-temperature LIBs and low-temperature battery management systems.展开更多
文摘Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I, the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different front that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I. For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.
基金supported by the National Nature Science Foundation of China(Nos.22305066 and 52372041).
文摘High-temperature microwave absorbing materials(MAMs)and structures are increasingly appealing due to their critical role in stealth applications under harsh environments.However,the impedance mismatch caused by increased conduction loss often leads to a significant decline in electromagnetic wave absorp-tion(EMWA)performance at elevated temperatures,which severely restricts their practical application.In this study,we propose a novel approach for efficient electromagnetic wave absorption across a wide temperature range using reduced graphene oxide(RGO)/epoxy resin(EP)metacomposites that integrate both electromagnetic parameters and metamaterial design concepts.Due to the discrete distribution of the units,electromagnetic waves can more easily penetrate the interior of materials,thereby exhibiting stable microwave absorption(MA)performance and impedance-matching characteristics suitable across a wide temperature range.Consequently,exceptional MA properties can be achieved within the tem-perature range from 298 to 473 K.Furthermore,by carefully controlling the structural parameters in RGO metacomposites,both the resonant frequency and effective absorption bandwidth(EAB)can be optimized based on precise manipulation of equivalent electromagnetic parameters.This study not only provides an effective approach for the rational design of MA performance but also offers novel insights into achieving super metamaterials with outstanding performance across a wide temperature spectrum.
基金supported by the National Natural Science Foundation of China(32372223)the National Key Research and Development Program of China(2022YFD2301404)+1 种基金the College Students'Innovationand Entrepreneurship Training Program of Anhui Province,China(S202210364136)the Natural Science Research Project of Anhui Educational Committee,China(2023AH040133).
文摘Low temperature(LT)in spring has become one of the principal abiotic stresses that restrict the growth and development of wheat.Diverse analyses were performed to investigate the mechanism underlying the response of wheat grain development to LT stress during booting.These included morphological observation,measurements of starch synthase activity,and determination of amylose and amylopectin content of wheat grain after exposure to treatment with LT during booting.Additionally,proteomic analysis was performed using tandem mass tags(TMT).Results showed that the plumpness of wheat grains decreased after LT stress.Moreover,the activities of sucrose synthase(SuS,EC 2.4.1.13)and ADP-glucose pyrophosphorylase(AGPase,EC 2.7.7.27)exhibited a significant reduction,leading to a significant reduction in the contents of amylose and amylopectin.A total of 509 differentially expressed proteins(DEPs)were identified by proteomics analysis.The Gene Ontology(GO)enrichment analysis showed that the protein difference multiple in the nutritional repository activity was the largest among the molecular functions,and the up-regulated seed storage protein(ssP)played an active role in the response of grains to LT stress and subsequent damage.The Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis showed that LT stress reduced the expression of DEPs such as sucrose phosphate synthase(SPS),glucose-1-phosphate adenylyltransferase(glgC),andβ-fructofuranosidase(FFase)in sucrose and starch metabolic pathways,thus affecting the synthesis of grain starch.In addition,many heat shock proteins(HsPs)were found in the protein processing in endoplasmic reticulum pathways,which can resist some damage caused by LT stress.These findings provide a new theoretical foundation for elucidating the underlying mechanism governing wheat yield developmentafterexposuretoLTstress inspring.
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Under the auspices of National Natural Science Foundation of China(No.42201374,42071359)。
文摘The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains limited.In this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal forest.The estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario datasets.The sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime temperature.The LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN model.By incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is achieved.Furthermore,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study area.The simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate scenarios.This study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.
基金supported by the Director Fund Project provided by the Institute of Plant Nutrition,Resources and Environment,Beijing Academy of Agriculture and Forestry Sciences(No.YZS202101)the Youth Fund Project provided by Beijing Academy of Agriculture and Forestry Sciences(No.QNJJ202125)China Agriculture Research System of MOF and MARA.
文摘The dissolved organic matter(DOM)with high mobility and reactivity plays a crucial role in soil.In this study,the characteristics and phytotoxicity ofDOMreleased fromthe hydrochars prepared from different feedstocks(cowmanure,corn stalk and Myriophyllum aquaticum)under three hydrothermal carbonization(HTC)temperatures(180,200 and 220°C)were evaluated.The results showed that the hydrochars had high dissolved organic carbon content(20.15 to 37.65 mg/g)and its content showed a gradual reduction as HTC temperature increased.Three fluorescent components including mixed substance of fulvic acid-like and humic acid-like substances(C1,30.92%-58.32%),UVA humic acid-like substance(C2,25.27%-29.94%)and protein-like substance(C3,11.74%-41.92%)were identified in hydrochar DOM by excitation emission matrix spectra coupled with parallel factor analysis.High HTC temperature increased the relative proportion of aromatic substances(C1+C2)and humification degree of hydrochar DOM from cow manure,while it presented adverse effects on the hydrochar DOM from corn stalk and Myriophyllum.aquaticum.The principal component analysis suggested that feedstock type and HTC temperature posed significant effects on the characteristics of hydrochar DOM.Additionally,seed germination test of all hydrochar DOM demonstrated that the root length was reduced by 8.88%-26.43%in contrast with control,and the germination index values were 73.57%-91.12%.These findings provided new insights into the potential environmental effects for hydrochar application in soil.
文摘The global climate change and ocean acidification brought about by the anthropogenic release of carbon dioxide gas into the air is considered one of the greatest problems facing marine life.In this research,the interactions between two species of fish(the gold mollies and tiger barb)were investigated under two different environmental conditions,an elevated temperature of 28°C and a low pH of 5 and a normal pH of 7 and a normal temperature of 24°C.The mollies at pH 7 and a temperature of 24°C exhibited scary interactions with the tiger barb.They were scared and ran fast away from the tiger barb.At the same time,the mollies at pH 5 and a temperature of 28°C interacted normally as though both species were one species showing behavioral changes due to these two stressors(pH 5 and elevated temperature 28°C).This could be the only research that has addressed how the kinematics and swimming interactions of two species of fish changed in response to elevated temperature and low pH.
文摘A metal-sensitive diaphragm fiber optic pressure sensor with temperature compensation is developed for pressure monitoring in high-temperature environments,such as engine fuel systems,oil and gas wells,and aviation hydraulic systems.The sensor combines a metal-sensitive diaphragm and a sapphire wafer to form a temperature-pressure dual Fabry-Perot(FP)interference cavity.A cross-correlation signal demodulation algorithm and a temperature decoupling method are utilized to reduce the influence of temperature crosstalk on pressure measurement.Experimental results show that the maximum nonlinear error of the sensor pressure measurement is 0.75%full scale(FS)and 0.99%FS at room temperature and 300°C,respectively,in a pressure range of 0−10 MPa and 0−1.5 MPa.The sensor’s pressure measurement accuracy is 1.7%FS when using the temperature decoupling method.The sensor exhibits good static pressure characteristics,stability,and reliability,providing an effective solution for high-temperature pressure monitoring applications.
基金supported by China Agriculture Research System of MOF and MARA(Grant No.CARS23-B10)The Major Science and Technology Projects in Hainan Province(Grant No.ZDKJ2021005)+1 种基金Key R&D projects in Shandong Province(Grant No.LJNY202106)Central Public-interest Scientific Institution Basal Research Fund(Grant No.IVF-BRF2023006)。
文摘Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses.It has been widely applied to produce solanaceous and melon vegetables.Temperature is an important external factor affecting graft formation.However,the molecular mechanism by which external ambient temperature affects tomato graft formation remains unclear.In this study,we demonstrated that elevating ambient temperature during grafting to 35℃ for more than 24 h after grafting accelerated vascular reconnection.We generated self-or heterografted combinations between phyB1B2 and pif4 loss-of-function mutant and wild-type plants,and were mutants unresponsive to graft formation at elevated ambient temperature.In addition,elevated ambient temperature induced SlPIF4 expression during grafting.SlPIF4 directly binds the promoters of auxin biosynthesis genes SlYUCCAs and activates their expression.Further investigation revealed auxin accumulation in the graft junction under elevated ambient temperature.The results illuminate the mechanism by which the PHYB-PIF4-auxin module promotes tomato graft formation in response to elevated ambient temperature.
基金Project(2018XK2301) supported by the Change-Zhu-Tan National Independent Innavation Demonstration Zone Special Program,China。
文摘The ductile-to-brittle transition temperature(DBTT)of high strength steels can be optimized by tailoring microstructure and crystallographic orientation characteristics,where the start cooling temperature plays a key role.In this work,X70 steels with different start cooling temperatures were prepared through thermo-mechanical control process.The quasi-polygonal ferrite(QF),granular bainite(GB),bainitic ferrite(BF)and martensite-austenite constituents were formed at the start cooling temperatures of 780℃(C1),740℃(C2)and 700℃(C3).As start cooling temperature decreased,the amount of GB decreased,the microstructure of QF and BF increased.Microstructure characteristics of the three samples,such as high-angle grain boundaries(HAGBs),MA constituents and crystallographic orientation,also varied with the start cooling temperatures.C2 sample had the lowest DBTT value(−86℃)for its highest fraction of HAGBs,highest content of<110>oriented grains and lowest content of<001>oriented grains parallel to TD.The high density of{332}<113>and low density of rotated cube{001}<110>textures also contributed to the best impact toughness of C2 sample.In addition,a modified model was used in this paper to quantitatively predict the approximate DBTT value of steels.
基金Supported by Natural Science Foundation of Hainan Province(320MS108)Scientific and Technological Innovation Team of the National Center for Tropical Agricultural Science,Chinese Academy of Tropical Agricultural Sciences(CATASCXTD202303)Key Laboratory of Genetic Resources Utilization of Spice and Beverage Crops,Ministry of Agriculture and Rural Affairs,Hainan Provincial Key Laboratory of Genetic Improvement and Quality Regulation for Tropical Spice and Beverage Crops,or Hainan Provincial Engineering Research Center for Tropical Spice and Beverage Crops(2019xys007).
文摘[Objectives]To explore the effects of high soil temperature stress on microorganisms utilizing different carbon sources in the rhizosphere of pepper seedlings.[Methods]Using seedlings of the main pepper cultivar‘Reyin 1’as experimental materials,five soil temperature gradients(25,30,35,40,and 45℃)were established.After a 96 d cultivation,soil nutrient content and soil microbial functional diversity were measured to elucidate the impact of high soil temperature on the soil microenvironment.[Results]As soil temperature increased,the contents of total nitrogen,alkaline hydrolyzable nitrogen,available phosphorus,and rapidly available potassium generally showed a decreasing trend.However,under the 45℃ treatment,the contents of total nitrogen,available phosphorus,and rapidly available potassium were the highest among all treatments,although the alkaline hydrolyzable nitrogen content was significantly lower compared to the other treatments.BIOLOG analysis revealed that with increasing soil temperature,the average soil microbial absorbance value and the Shannon diversity index decreased significantly.In contrast,the Shannon evenness index and the Simpson dominance index showed no significant differences across the different temperature treatments.This indicates that as soil temperature rises,the carbon source utilization capacity of the soil microbial community decreases,leading to reduced overall carbon metabolic activity and microbial functional diversity,while the dominant microbial populations remained unchanged during this process.Principal component analysis further confirmed effective separation among the different temperature treatments,suggesting that high soil stress significantly altered the structure of the soil microbial community.[Conclusions]In practical production,appropriate measures should be taken to decrease soil temperature to create a favorable rhizosphere microenvironment and thereby promote crop growth.
基金supported by the National Key R&D Program of China(NO.2024YFB3409900)the China Postdoctoral Science Foundation(No.2023M730845)the Heilongjiang Postdoctoral Fund(No.LBH-Z23182).
文摘Soft actuators endowed with self-sensing capability become highly sought after in recent years.Ti3C2Tx MXene is expected to be used in the development of self-sensing actuators due to its outstanding physical and chemical properties.However,achieving precise deformation feedback of MXene-based actuators remains a challenge,as the resistance change of MXene is not only affected by deformation,but also by temperature,and the decoupling is difficult.Here,a composite ink with temperature self-compensation(0.00125%·°C^(−1) of temperature coefficient of resistance)is fabricated by combining MXene and graphite with opposite temperature coefficients of resistance.The composite ink can be written on a variety of substrates,including glass,cellulose paper,and various polymers.Based on this,an ink-cellulose/polymer composite actuator with self-sensing function is actualized.The actuator can achieve accurate real-time deformation feedback by monitoring the resistance signal of ink-cellulose layer,which shows a high linear sensitivity(gauge factor~14.5,coefficient of determination(R^(2))>0.99),thereby realizing the perception of touch behavior and distinguishing objects with different weights,softness,and roughness.Besides,a series of biomimetic devices and soft robots with programmable movements(rolling and self-sustained oscillating)are also demonstrated.The results offer new insights for the development of the self-sensing actuators.
基金supported by the National Natural Sciences Foundation of China(No.12172295)。
文摘This work attempts to optimize Graphene nanoplatelets(GPLs)distribution in the face sheet of sandwich plates to pursue the minimum thermal deflection and transverse shear stresses at interfaces.Thus,an Improved Legendre Higher-order plate Theory combined with Isogeometric Analysis(ILHT-IGA)is,first,proposed to accurately predict thermomechanical behaviors of GPLs-reinforced sandwich plates,which can ensure the reliability of the optimized results.Then,an accelerated multi-objective optimization approach is proposed to optimize thermomechanical behaviors.The trained machine learning algorithm based on ILHT-IGA is employed as a surrogate model to accelerate the optimization process.Finally,X-shaped GPLs distribution can provide the maximum stiffness to resist thermal expansion.However,X-shaped GPLs distribution on face sheets will result in large difference of stiffnesses at adjacent surfaces of face sheets and core layer.Thus,transverse shear stresses at interfaces are obviously increased.To avoid a sudden increase of transverse shear stresses at interfaces,an alternative optimized GPLs distribution has been obtained,where GPLs gradually increase toward the upper and lower surfaces of face sheets and suddenly decrease near the surface of face sheets.Such distributions can effectively enhance the stiffness of sandwich plates to resist thermal expansion behaviors and decrease transverse shear stresses at interfaces.
基金financially supported by the Outstanding Youth Foundation of Jiangsu Province of China(No.BK20211548)Yangzhou Science and Technology Plan Project(No.YZ2023246)+1 种基金China Scholarship Council(No.202308320445)the Postgraduate Research and Practice Innovation Program of Jiangsu Province of China(No.KYCX23_3551)
文摘Bismuth-doped antimony tungstate(Bi-doped Sb_(2)WO_(6))microspheres were synthesized via a novel hydrothermal synthesis approach.These microspheres were then used as active layers in gas sensors for the detection of carbon dioxide(CO_(2)),a significant greenhouse gas and a critical parameter for evaluating air quality.The incorporation of bismuth significantly enhances the gas-sensing performance of the Sb_(2)WO_(6)microspheres,with the 4%Bidoped sensing active layer achieving a remarkable response value of 15 when exposed to 200 ppm of CO_(2),outperforming the undoped Sb_(2)WO_(6).Furthermore,the selectivity of the 4%Bi-Sb_(2)WO_(6)sensor toward CO_(2)gas was enhanced relative to the Sb_(2)WO_(6)sensor.The fundamental mechanisms of gas sensing and the factors contributing to the improved CO_(2)response of 4%Bi-Sb_(2)WO_(6)micro spheres were investigated using density functional theory.Bi-doped Sb_(2)WO_(6)materials exhibit significant advantages in gas-sensing applications,including improved conductivity,enhanced gas adsorption capacity,increased reaction rates,good chemical stability,excellent selectivity,and the ability to adjust electron density.These characteristics enable Bi-doped Sb_(2)WO_(6)to demonstrate higher sensitivity and rapid response capabilities in gas sensors,making it suitable for practical applications.
基金supports by the National Natural Science Foundation of China(No.52274311)the Natural Science Research Project of Anhui Educational Committee,China(No.2023AH051081).
文摘In order to avoid poor machinability caused by excessive hardness under high-silicon conditions in the traditional free-cutting graphited steel,it is important to develop a suitable silicon-saving,aluminum-containing free-cutting steel.This study investigated the microstructure and graphite precipitation behavior of Fe–0.58C–1.0Al(wt%)steels with varying silicon contents(0.55wt%–2.67wt%)after tempering at different temperatures(680℃,715℃).The tempering structure and the precipitation behavior of graphite and Fe_(3)C in Fe–0.58C–1.0Al steels were systematically studied by optical microscopy(OM),field emission scanning electron microscopy(FESEM),and electron microprobe analyzer(EPMA).The results showed that,at both tempering temperatures,the microstructure of 0.55wt%Si steel is ferrite+granular Fe_(3)C,and the microstructures of 1.38wt%–2.67wt%Si steels are ferrite+petaloid graphite+granular Fe_(3)C.With increasing Si content from 1.38wt%to 2.67wt%at constant tempering temperature,the number density of graphite particles increases,though their average size decreases.Meanwhile,the number density and average size of Fe_(3)C in experimental steels continuously decrease with the increase of Si content.For 0.55wt%Si steel without graphite precipitation,increasing tempering temperature promotes the accumulation and growth of Fe_(3)C.For 1.38wt%–2.67wt%Si steels with graphite precipitation,higher tempering temperature promotes graphite particles growth while accelerating the decomposition and refinement of Fe_(3)C.Furthermore,compared with the experimental steels containing 0.55wt%Si,1.38wt%Si,and 2.67wt%Si,the 1.89wt%Si steel exhibits significantly lower hardness.Especially,when tempered at 715℃,Fe–0.58C–1.0Al steel with 1.89wt%Si exhibits enhanced graphitization behavior and reduced hardness,which is nearly HV 20 lower than previously reported Fe–0.55C–2.33Si steel.
基金supported by National Key R&D Program of China(grant 2023YFD2400600)National Natural Scientific Foundation of China(grant 32373147)China Agriculture Research System(grant CARS-47-G10).
文摘Temperature is well known as the major environmental factor that influences survival and growth of fish,which are poikilo-thermic animals.However,it is still unclear about the mechanism that underscores thermal-controlled fish physiology,especially nutritional utilization and metabolism,which are vitally important in aquaculture.In the present study,juvenile turbot was force-fed with amino acid mixture and its postprandial absorption,nutrient sensing and metabolism under low(12,15℃),optimal(18℃)to high(21,24℃)temperatures were explored.Intestinal trypsin and lipase activity were highly sensitive to water temperature,and highest under optimal temperatures for turbot,whereas amylase remained constant.Selective groups of intestinal amino acid transporters were upregulated in cold temperatures,but the amino acid absorption capability was increased with rising temperature.The mechanistic target of rapamycin(mTOR)signaling pathway was most active at optimal temperature.Postprandial muscle protein deposition achieved maximum level under optimal temperature.Amino acid catabolic enzymes branched-chain aminotransferase and branched-chainα-keto acid dehydrogenase activities were increased with rising temperatures.High temperature increased significantly energy metabolism and stimulated cel-lular stress in liver.These findings highlight the critical role of temperature in modulating amino acid dynamics,metabolic processes and stress responses in juvenile turbot,providing valuable insights for optimizing aquaculture practices.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274373,12274372,and 12204259)the Natural Science Foundation of Henan Province(Grant No.242300421155)+2 种基金the Key Research Projects of Higher Education Institutions in Henan Province(Grant No.25A140008)the Science and Technology Base and Talent Project of Guangxi,China(Grant No.AD21220154)the Central Plains Science and Technology Innovation Youth Top Notch Talents.
文摘The properties and creation of optical centers in diamond are essential for applications in quantum technology.Here,we study the photoluminescence(PL)spectroscopy behavior at low temperatures of diamond subjected to electron irradiation and annealing heat treatment.Through temperature variation testing,it was found that the NVcenter intensity of diamond with a nitrogen content of 150 ppm before treatment is insensitive to the experimental temperature,but significantly increases with decreasing temperature after treatment,showing sensitivity to temperature.In addition,the H3 center also shows an increasing trend with decreasing temperature.The results of annealing diamond with a nitrogen content of 730 ppm showed that even at a low temperature of 93 K,no NV^(-)centers were detected,but there were a large number of Ni-N related centers,especially NE8 centers.Our findings can promote a deeper understanding of the behavioral characteristics of HPHT-diamond optical centers in low-temperature environments.
基金supported by the National Natural Science Foundation of China(Nos.52474403,52364050 and 52301137)Guizhou Provincial Program on Commercialization of Scientific and Technological Achievements(No.[2023]001)+2 种基金Guizhou Province Science and Technology Project(No.[2022]050)Guiyang city Science and Technology Project(No.[2023]48-16)the Central Government in Guidance of Local Science and Technology Development Funds(No.[2024]032).
文摘The serrated flow behavior,known as the Portevin-Le Chatelier(PLC)effect,is commonly observed during high-temperature deformation.In this study,we report a serrated flow behavior in FeCoCrNiMo0.2 high-entropy alloy(HEA),which is mediated by nano-twinning and phase transformation at cryogenic temperatures.During uniaxial tensile deformation at 77 K,the alloy exhibited the formation of high-density deformation nano-twinning,cross-twinning,stacking faults(SFs)and Lomer-Cottrell locks(L-C locks).Additionally,the lower stacking fault energy(SFE)at low temperatures promotes the formation of the 9R phase.The high-density twin boundaries effectively hinder dislocation movement,leading to the instability of plastic deformation and promoting the serrated flow behavior.Furthermore,the rapid and unstable transformation of the 9R phase contributes to the pronounced serrated flow behavior.Nano-twinning,SFs,cross-twinning,L-C locks and 9R phase collectively induce a dynamic Hall-Petch effect,enhancing the strength-ductility synergy and strain-hardening ability of deformed alloy at 77 K.Our work provides valuable insights into the mechanism of tensile deformation at cryogenic temperatures in single-phase FCC HEA.
基金Funded by the National Natural Science Foundation of China(No.51878227)。
文摘Microstructures and properties of mortar using ammonium phosphate and potassium phosphate were tested and compared in this case.Moreover,two cementitious additions and two lightweight aggregates,including fly ash,redispersible latex powder,ceramsite sand,and rubber powder,were respectively tried to be applied in magnesium ammonium phosphate cement mortar in order to modify the microstructures and properties.The experimental results show that potassium phosphate is not suitable for magnesium phosphate cement mortar for cold region construction purpose.Although fly ash can bring positive modification in the condition of normal temperature curing,it brings negative effects in the condition of sub-zero temperature curing.Either redispersible latex powder or ceramsite sand can improve the freeze-thaw cycling resistance of magnesium phosphate cement mortar in the conditions of low temperature coupled with freeze-thaw cycling,but only the ceramsite sand can improve both mechanical properties and freeze-thaw cycling resistance.The modification caused by ceramsite sand is mainly due to the exceptional bonding strength between hardened cement paste and the porous surface of ceramsite and the porous structure of ceramsite for the release of frost heave stress.
基金financially supported by the National Natural Science Foundation of China(NSFC,Grant number U20A20310)the Program of Shanghai Academic/Technology Research Leader(Grant number 22XD1423800)。
文摘The degradation of Lithium-ion batteries(LIBs)during cycling is particularly exacerbated at low temperatures,which has a significant impact on the longevity of electric vehicles,energy storage systems,and consumer electronics.A comprehensive understanding of the low-temperature aging mechanisms throughout the whole life cycle of LIBs is crucial.However,existing research is limited,which typically focuses on capacity degradation to 80%.To fill this gap,this paper conducts low-temperature cyclic aging tests at three different charging rates.The investigation employs differential voltage analysis,the distribution of relaxation times technique,and disassembly characterization to explore both thermodynamic degradation and kinetic degradation,alongside a correlation analysis of the factors influencing these degradation processes.The results reveal two distinct knee points in the capacity decline of LIBs during the whole life cycle,in contrast to prior studies identifying only one.Before the first knee point,the thickening of the SEI film dominates capacity loss,with higher charging rates accelerating the process.After the first knee point,the main degradation mechanisms shift to lithium plating and the fracture of the positive electrode active particles.These two aging factors become more pronounced with ongoing cycling,culminating in a second knee point in capacity decline.Notably,a novel finding demonstrates that after the second knee point,capacity degradation progresses faster at lower charging rates compared to medium rates.The reason is the fracture of graphite particles also becomes a critical contributor to the severe capacity degradation at lower charging rates.These insights will guide the designs of next-generation low-temperature LIBs and low-temperature battery management systems.
