Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this ...Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.展开更多
1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-...1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.展开更多
Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous ...Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous quantitative analyses often simplified the chorus dispersion relation by using the cold plasma assumption.However,the applicability of the cold plasma assumption is doubtful,especially during geomagnetic disturbances.We here present a systematic statistical analysis on the validity of the cold plasma dispersion relation of chorus waves based on observations from the Van Allen Probes over the period from 2012 to 2018.The statistical results show that the observed magnetic field intensities deviate substantially from those calculated from the cold plasma dispersion relation and that they become more pronounced with an increase in geomagnetic activity or a decrease in background plasma density.The region with large deviations is mainly concentrated in the nightside and expands in both the radial and azimuthal directions as the geomagnetic activity increases or the background plasma density decreases.In addition,the bounce-averaged electron scattering rates are computed by using the observed and cold plasma dispersion relation of chorus waves.Compared with usage of the cold plasma dispersion relation,usage of the observed dispersion relation considerably lowers the minimum resonant energy of electrons and lowers the scattering rates of electrons above tens of kiloelectronvolts but enhances those below.Furthermore,these differences are more pronounced with the enhancement of geomagnetic activity or the decrease in background plasma density.展开更多
Additive manufacturing (AM) of high-strength metallic alloys frequently encounters detrimental distortion and cracking, attributed to the accumulation of thermal stresses. These issues significantly impede the practic...Additive manufacturing (AM) of high-strength metallic alloys frequently encounters detrimental distortion and cracking, attributed to the accumulation of thermal stresses. These issues significantly impede the practical application of as-printed components. This study examines the Mg-15Gd-1Zn-0.4Zr (GZ151K, wt.%) alloy, a prototypical high-strength casting Mg-RE alloy, fabricated through laser powder bed fusion (LPBF). Despite achieving ultra-high strength, the GZ151K alloy concurrently exhibits a pronounced cold-cracking susceptibility. The as-printed GZ151K alloy consists of almost fully fine equiaxed grains with an average grain size of merely 2.87 µm. Subsequent direct aging (T5) heat treatment induces the formation of dense prismatic β' precipitates. Consequently, the LPBF-T5 GZ151K alloy manifests an ultra-high yield strength of 405 MPa, surpassing all previously reported yield strengths for Mg alloys fabricated via LPBF and even exceeding that of its extrusion-T5 counterpart. Interestingly, as-printed GZ151K samples with a build height of 2 mm exhibit no cracking, whereas samples with build heights ranging from 4 to 18 mm demonstrate severe cold cracking. Thermal stress simulation also suggests that the cold cracking susceptibility increases significantly with increasing build height. The combination of high thermal stress and low ductility in the as-printed GZ151K alloy culminates in a high cold cracking susceptibility. This study offers novel insights into the intricate issue of cold cracking in the LPBF process of high-strength Mg alloys, highlighting the critical balance between achieving high strength and mitigating cold cracking susceptibility.展开更多
The complex of calcineurin B-like protein(CBL)and CBL-interacting protein kinase(CIPK)serves as key components in calcium-sensing,orchestrating various signals crucial for plant growth,development,and responses to bio...The complex of calcineurin B-like protein(CBL)and CBL-interacting protein kinase(CIPK)serves as key components in calcium-sensing,orchestrating various signals crucial for plant growth,development,and responses to biotic and abiotic stresses.However,the mechanism underlying the response of this module to cold stress and its role in flower development in wintersweet(Chimonanthus praecox)remains unclear.Through expression pattern analysis,calcium ion(Ca^(2+))concentration assays,correlation analysis,and linear regression analysis,we found that the[Ca^(2+)],along with CpCBL8 and CpCIPK9 expression levels in wintersweet flower buds(FBs),significantly decreased during the initial flowering stage when the chilling requirement reached 570 chill units(CU).Notably,there was a significant positive correlation between[Ca^(2+)]and CpCBL8 expression.Ca^(2+)increased the expression of Cp CBL8 and CpCIPK9 in FBs,causing a significant delay in the flowering of wintersweet.Furthermore,the function of CpCBL8 was studied using heterologous transformation.Overexpression of CpCBL8 significantly delayed flowering time and significantly reduced cold tolerance and altered the expression pattern of endogenous genes related to low-temperature stress and flower development in transgenic Arabidopsis thaliana.Additionally,transcriptome analysis of chilling-induced dormancy breaking and flower bud enlargement revealed that CpCBL8 and CpCIPK9 were negatively regulated by cold,and the expression pattern of endogenous genes related to flower development and cold stress in wintersweet were similar to that of in A.thaliana.Moreover,protein-protein interaction(PPI)analysis revealed that CpCBL8 and CpCIPK9 interacted in the plasma membrane and nucleus.On the basis of these findings,we speculated that the CpCBL8-CpCIPK9 module plays a crucial role in regulating responses to cold stress and flower development in wintersweet.This study elucidated molecular mechanisms through which the downregulation of the Ca^(2+)-induced CpCBL8-CpCIPK9 module results in dormancy breaking and enhances cold tolerance.This study provides valuable insights for the cultivation of new varieties of wintersweet with increased ornamental value and enhanced cold stress tolerance.展开更多
A recent discovery in rice has revealed an elegant trick of nature:crops can teach their later generations to survive the cold through inherited memories written in chemical marks on the DNA letters,representing the f...A recent discovery in rice has revealed an elegant trick of nature:crops can teach their later generations to survive the cold through inherited memories written in chemical marks on the DNA letters,representing the first clear demonstration of what scientists call the“inheritance of acquired characteristics”-a phenomenon that biologists have debated for over two centuries.展开更多
The addition of cold flow improvers(CFIs)is considered as the optimum strategy to improve the cold flow properties(CFPs)of diesel fuels,but this strategy is always limited by the required large dosage.To obtain low-do...The addition of cold flow improvers(CFIs)is considered as the optimum strategy to improve the cold flow properties(CFPs)of diesel fuels,but this strategy is always limited by the required large dosage.To obtain low-dosage and high-efficiency CFIs for diesel,1,2,3,6-tetrahydrophthalic anhydride(THPA)was introduced as a third and polar monomer to enhance the depressive effects of alkyl methacrylatetrans anethole copolymers(C_(14)MC-TA).The terpolymers of alkyl methacrylate-trans anethole-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-TA-THPA)were synthesized and compared with the binary copolymers of C_(14)MC-TA and alkyl methacrylate-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-THPA).Results showed that C_(14)MC-THPA achieved the best depressive effects on the cold filter plugging point(CFPP)and solid point(SP)by 11℃and 16℃at a dosage of 1250 mg/L and monomer ratio of 6:1,while 1500mg/L C_(14)MC-TA(1:1)reached the optimal depressive effects on the CFPP and SP by 12℃and 18℃.THPA introduction significantly improved the depressive effects of C_(14)MC-TA.Lower dosages of C_(14)MCTA-THPA in diesel exerted better improvement effects on the CFPP and SP than that of C_(14)MC-TA and C_(14)MC-THPA.When the monomer ratio and dosage were 6:0.6:0.4 and 1000 mg/L,the improvement effect of C_(14)MC-TA-THPA on diesel reached the optimum level,and the CFPP and SP were reduced by 13℃and 19℃,respectively.A 3D nonlinear surface diagram fitted by a mathematical model was also used for the first time to better understand the relationships of monomer ratios,dosages,and depressive effects of CFIs in diesel.Surface analysis results showed that C_(14)MC-TA-THPA achieved the optimum depressive effects at a monomer ratio of 6:0.66:0.34 and dosage of 1000 mg/L,and the CFPP and SP decreased by 14℃ and 19℃,respectively.The predicted results were consistent with the actual ones.Additionally,the improvement mechanism of these copolymers in diesel was also explored.展开更多
Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively ...Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively analyzed from the aspects of circulation background,circulation situation,influence system,dynamic conditions,water vapor conditions,etc.The results show that the cold wave weather process appeared during the transition of circulation pattern from zonal to meridional type in middle and high latitudes in the northern Hemisphere.Due to the development of the European trough,the strong warm advection was transported to the Ural Ridge,making it strongly developed.The strong northerly wind belt in front of the ridge moved southwards.The warm advection at the rear of the transverse trough and the cold advection in the southeast in front of the transverse trough on the northwest side of Lake Baikal caused the transverse trough to turn upright and moved southwards,and the longitude of the circulation increased continuously to guide cold air to move southwards,resulting in this strong cold air process.The large ground pressure gradient caused by strong cold air and the frontogenesis of strong surface cyclone led to the gale in North China.展开更多
Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was desi...Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was designed for cold storage applications.The optimal number of PCM plates was determined through numerical simulations to meet the required cold storage temperature and control time.Additionally,the air temperature field,flow field,and melting characteristics of the PCMplates during the cooling release process were analyzed.The effects of plate positioning and thickness on the cooling release performance were further investigated.The results indicated that when 64PCMplateswere used,the duration formaintaining temperatures below−18℃increased from0.6 h to approximately 16.94 h.During the cooling release process,the temperature field in the cold storage exhibited stratification,and the melting of the PCM plates was non-uniform.Placing the PCM plates at the top or within the interlayers without cargo above proved more effective,with their cooling release power being approximately twice that of the PCM plates placed in the interlayers with cargo above.Furthermore,reducing the thickness of the PCMplates from15 to 7.5mmresulted in a 3.6-h increase in the time below−18℃and a 4.5-h reduction in the time required to reach 80%liquid phase fraction.展开更多
Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibit...Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibits a cold crystallization behavior.This abnormal behavior causes unstable mechanical properties at low-temperature and limits its applications in shape memory devices where crystallization is an essential mechanism.To analyze the unusual phenomenon,we compared different ether polyols focusing on symmetry characteristics and the evenodd effect of carbon backbones.It is found that PO3G has a slow crystallization rate because its ether linkages require specific chain arrangement for attractive interactions.Consequently,a thermal learning mechanism is developed to restore the normal crystallization behavior of elastomers synthesized from the bio-polyol.Repetitive heating and cooling cycles with high-temperature annealing induce urethane exchange reaction and reconstruct the chain orientations for fast crystallization.Results suggest the degree of crystallizations in polyurethane elastomer can be precisely controlled by introducing repetitive thermal treatments to enhance the potential applications of bio-polyols in polymer industries.展开更多
Cold tolerance is one of the important traits for grapevine,especially in regions with extremely low temperatures in winter.Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared wit...Cold tolerance is one of the important traits for grapevine,especially in regions with extremely low temperatures in winter.Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared with Vitis vinifera.However,metabolites that contribute to the cold tolerance of V.amurensis remain unknown.Here,the metabolomics of buds from V.amurensis‘Zuoshan-1'during cold acclimation(CA)were identified,and cold-sensitive cultivar(V.vinifera‘Jingzaojing')was used as the control.The buds were collected in October,November,and December in 2016 and 2018.The cold hardiness of the buds increased during CA in the two grapevines.However,browning was observed only in V.vinifera buds at temperature below-10℃.Among detected metabolites from buds,443 metabolites were overlapped between two years.Forty-four and thirty differentially accumulated metabolites(DAMs)were identified in V.amurensis and V.vinifera,respectively.Ten DAMs including monoacylglycerol(MAG,18:2)isomer 1,trehalose 6-phosphate,and D-glucose showed identical variations in the two grapevines,indicating conserved CA responses within the Vitis genus.Eighteen DAMs exhibited higher accumulation in V.amurensis than in V.vinifera.Maltotetraose,D-glucoronic acid,L-aspartic acid,azelaic acid,and 4-hydroxybenzoic acid were reported to accumulate during CA in other plants.Enhanced cold tolerance was detected in grapevine leaves with exogenous 5 mmol L^(-1)L-aspartic acid and 1%proanthocyanidins.Potential contributions of other DAMs found in V.amurensis such as Cyanidin 3-O-glucoside need to be further elucidated.Thus,eighteen metabolites accumulated in V.amurensis can be used for practical application in improvement of cold resistance in grapevine.Our findings provide new insights into understanding the cold hardiness of V.amurensis.展开更多
Objective The role of cold spells of different intensities in the economic burden of death is crucial for health adaptation to climate change,especially in a multi-site setting.The objective of the study was to explor...Objective The role of cold spells of different intensities in the economic burden of death is crucial for health adaptation to climate change,especially in a multi-site setting.The objective of the study was to explore the economic burden of mortality attributable to cold spells Methods We performed a two-stage time-series analysis using the Value of Statistical Life(VSL)approach to evaluate the economic impact of mortality related to cold spells of varying lengths and intensities.This analysis employed a case-crossover design,with a distributed lag nonlinear model(DLNM)used for analysis.Analysis was stratified according to age,sex,and region of origin.The results of the assessment show that cold spells have an enormous impact on the economic losses of mortality due to climate change and aging.Results Totally,8.3%(95%CI:0.0%,16.0%)to 13.8%(95%CI:1.0%,24.8%)of VSL were ascribed to cold spells,accounting for economic losses of 4.71(95%CI:0.34,8.47)to 11.45(95%CI:0.00,21.00)billion CNY,in the cold season.The population aged over 65 y and females are particularly vulnerable.Economic impacts in warmer regions,such as the southern and subtropical zones,are more extensive than those in the northern and temperate zones.Conclusion Customizing cold spell prevention measures for vulnerable populations or regions is vital to alleviating the socioeconomic burden.展开更多
The variations of the frontogenetic activity of cold filament driven by the different angle(θ=0°,22.5°,45°,67.5°,and 90°)of the wind and wave fields and the filament axis are studied by non h...The variations of the frontogenetic activity of cold filament driven by the different angle(θ=0°,22.5°,45°,67.5°,and 90°)of the wind and wave fields and the filament axis are studied by non hydrostatic large eddy simulation.Conversion between the frontogenesis and frontolysis of cold filament were created by the chang in the direction of secondary circulations.The changes in the direction of secondary circulation are induced by the Coriolis Effect regardless of wind direction and wave fields.The destructive action of the wind and wave fields on symmetry of the submesoscale flow fields becomes weak as the angle increases.The secondary downwelling jet induced by Stokes shear force is gradually close to that associated with secondary circulations as the angle changes fromθ=0°to 45°and then the downwelling jet is only created by secondary circulations forθ=67.5°and 90°.The frontogenetic intensity of cold filament may be impacted by the angle of the wind and wave fields and the filament axis.The reason is that firstly the odd-symmetry of secondary circulations enhances with the angle increasing,and secondary the secondary downwelling jet created the Stokes shear force gradually weakens and then disappears with the angle increasing.展开更多
In northern China,light and temperature are major limiting factors for plant growth,particularly during seed production and seedling establishment.While previous studies suggested a possible role for the MYB97 gene in...In northern China,light and temperature are major limiting factors for plant growth,particularly during seed production and seedling establishment.While previous studies suggested a possible role for the MYB97 gene in cold-stress,confirmation through documented evidence was lacking.In this study,we transformed the MYB97 gene from Iris laevigata into tobacco,and discovered that the gene boosted photosynthesis,photoprotection and resilience to cold.The transgenic tobacco seeds exhibited enhanced germination and accelerated seedling growth.Moreover,these plants had decreased levels of MDA(Malondialdehyde)and relative conductance,coupled with elevated concentrations of proline and soluble sugars.This response was accompanied by heightened activity of antioxidant enzymes during periods of cold stress(4 and−2℃).Exposure to low temperatures(0–15℃)also reduced heights but accentuated primary root growth in transgenic tobacco plants.Additionally,tobacco leaves showed an increased growth along with higher chlorophyll levels,net photosynthetic rates,stomatal conductance,transpiration rates and non-photochemical quenching coefficient.This study shows that IlMYB97(The MYB97 genes in I.laevigata)improves cold-resistance,and enhances photosynthesis and photoprotective ability,and thus overall growth and development.These findings would offer the genetic resources to further study cold resistance and photosynthesis.展开更多
In the realm of all-electric aircraft research,the integration of cathode-open proton exchange membrane fuel cells(PEMFC)with lithiumbatteries as a hybrid power source for small to medium-sized unmanned aerial vehicle...In the realm of all-electric aircraft research,the integration of cathode-open proton exchange membrane fuel cells(PEMFC)with lithiumbatteries as a hybrid power source for small to medium-sized unmanned aerial vehicles(UAVs)has garnered significant attention.The PEMFC,serving as the primary energy supply,markedly extends the UAV’s operational endurance.However,due to payload limitations and spatial constraints in the airframe layout of UAVs,the stack requires customized adaptation.Moreover,the implementation of auxiliary systems to facilitate cold starts of the PEMFC under low-temperature conditions is not feasible.Relying solely on thermal insulation measures also proves inadequate to address the challenges posed by complex low-temperature startup scenarios.To overcomethis,our study leverages the UAV’s lithium battery to heat the cathode inlet airflow,aiding the cathode-open PEMFC cold start process.To validate the feasibility of the proposed air-assisted heating strategy during the conceptual design phase,this study develops a transient,non-isothermal 3Dcathode-open PEMF Cunitmodel incorporating cathode air-assisted heating and gas-ice phase change.The model’s accuracy was verified against experimental cold-start data from a stack composed of identical single cells.This computational framework enables quantitative analysis of temperature fields and ice fraction distributions across domains under varying air-assisted heating powers during cold starts.Building upon this model,the study further investigates the improvement in cold start performance by heating the cathode intake air with varying power levels.The results demonstrate that the fuel cell achieves self-startup at temperatures as low as−13℃ under a constant current density of 100mA/cm^(2) without air-assisted heating.At an ambient temperature of−20℃,a successful start-up can be achieved with a heating power of 0.45 W/cm^(2).The temperature variation overtime during the cold start process can be represented by a sum of two exponential functions.The air-assisted heating scheme proposed in this study has significantly improved the cold start performance of fuel cells in low-temperature environments.Additionally,it provides critical reference data and validation support for component selection and feasibility assessment of hybrid power systems.展开更多
Temperature fluctuations challenge ectothermic species,particularly tropical fish dependent on external temperatures for physiological regulation.However,the molecular mechanisms through which low-temperature stress i...Temperature fluctuations challenge ectothermic species,particularly tropical fish dependent on external temperatures for physiological regulation.However,the molecular mechanisms through which low-temperature stress impacts immune responses in these species,especially in relation to chromatin accessibility and epigenetic regulation,remain poorly understood.In this study,we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia(Oreochromis niloticus),a tropical fish of significant economic importance,under cold stress.By analyzing cis-regulatory elements in open chromatin regions and their associated transcription factors(TFs),we construct a comprehensive transcriptional regulatory network(TRN)governing immune responses,including DNA damage-induced apoptosis.Our analysis identifies 119 TFs within the TRN,with Stat1 emerging as a central hub exhibiting distinct binding dynamics under cold stress,as revealed by footprint analysis.Overexpression of Stat1 in immune cells leads to apoptosis and increases the expression of apoptosis-related genes,many of which contain Stat1-binding sites in their regulatory regions,emphasizing its critical role in immune cell survival during cold stress.These results provide insights into the transcriptional and epigenetic regulation of immune responses to cold stress in tilapia and highlight Stat1 as a promising target for enhancing cold tolerance in tropical fish species.展开更多
Background:Cold temperatures cause blood vessels to constrict,shallow breathing,and slight thickening of the blood.Working in extremely cold environments can have negative effects on health,yet there are currently no ...Background:Cold temperatures cause blood vessels to constrict,shallow breathing,and slight thickening of the blood.Working in extremely cold environments can have negative effects on health,yet there are currently no effective biomarkers to monitor these health conditions.Proteins are important intermediate phenotypes that can provide a theoretical basis for understanding disease pathophysiology.Proteins in the circulatory system reflect the physiological status of individuals,and plasma proteins have significant potential as biomarkers for various health conditions.Methods:In this study,we employed the Mendelian randomization(MR)method to analyze the effects of freezing temperatures on over 2900 plasma proteins.Subsequently,the selected plasma proteins were subjected to causal analysis in relation to 55 diseases,including respiratory disorders,cardiovascular diseases,various cancers,and oral diseases.The aim was to identify proteins that could serve as biomarkers for health status.Results:Our results indicate that cold environments may affect the concentrations of 78 plasma proteins.Further MR analysis revealed that nine of these plasma proteins are associated with the risk of respiratory disorders,cardiovascular diseases,various cancers,and oral diseases.Conclusion:These proteins show promise as biomarkers for monitoring the hazards and risks faced by individuals working in cold environments.These findings provide valuable insights into the biological mechanisms underlying occupational hazards.展开更多
Bioremediation is an efficient and popular approach for domestic wastewater treatment while the pollutant discharge standards are difficult to achieve under low-temperature conditions. The application of cold-resistan...Bioremediation is an efficient and popular approach for domestic wastewater treatment while the pollutant discharge standards are difficult to achieve under low-temperature conditions. The application of cold-resistant bacteria has gained increasing attention, but direct introduction to sewage leads to poor environmental adaptability and low microbial activity. Biochar was used as a carrier to immobilize the bacteria to improve microbial survival and activity in this study. The basic physicochemical properties of bacteria immobilized by biochar and ammonium nitrogen removal efficiency were analyzed. The process mechanism of ammonium nitrogen removal was further explored using kinetic fitting and molecular simulation calculations. The results showed that biochar immobilization of cold-resistant bacteria achieved a significantly higher ammonium nitrogen removal rate of 0.88 mg/(L·h) compared to free mixed bacteria(0.74 mg/(L·h)) and biochar alone(0.22 mg/(L·h)). It also exhibited a removal efficiency of 96.56%, which was 15.02% and 72.58% higher than that of free mixed bacteria and biochar, respectively. Adsorption kinetics further revealed that the pseudosecond-order kinetic equation was a better fit for characterizing ammonia-nitrogen removal by biocharimmobilized cold-resistant bacteria. Combining microscopic morphology analysis and molecular simulations demonstrated that enriching functional groups on biochar enhanced its NH_4~+ adsorption capacity by increasing surface activity and polarity, as well as the biodegradation ability of NH_4~+ by improving the interactions between biochar and active enzymes. These findings provide valuable insights into developing more effective ways to improve wastewater treatment efficiency under low temperatures.展开更多
The coastal regions of Laizhou Bay are highly susceptible to cold surges.This study used ERA5 reanalysis data from 2007 to 2022 and employed a hybrid model that integrates single-particle Lagrangian trajectories to st...The coastal regions of Laizhou Bay are highly susceptible to cold surges.This study used ERA5 reanalysis data from 2007 to 2022 and employed a hybrid model that integrates single-particle Lagrangian trajectories to statistically analyze the paths and intensity characteristics of cold surges in the Laizhou Bay area.Based on this analysis,a comparative analysis of outbreak processes,formation mechanisms,and causes of three different types of cold surge pathways was conducted.Results indicate variations in the characteristics of different cold surge pathways.Cold surges along the northern pathway originate from the Kara Sea.From a circula-tion perspective,the presence of a warm ridge over the Ural Mountains leads to the formation of a blocking system and an inverted‘Ω’flow pattern over Siberia.In contrast,cold surges along the northwest pathway originate from the Barents Sea,the Kara Sea,and the plains of Eastern Europe,with a pre-outbreak circulation displaying a characteristic‘ridge-trough-ridge’pattern.Finally,cold surges along the western pathway originate from the Norwegian Sea and the nearby plains of Eastern Europe,transitioning from a blocking pattern to a‘ridge-trough-ridge’pattern before the outbreak,distinguishing them from the northern and northwest path-ways.This research provides a basis for forecasting cold surge events in Laizhou Bay and for disaster prevention and mitigation in the coastal regions.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52071040 and 51871036)Natural Science Foundation of Shandong Province,China(No.ZR2022QE008)China Postdoctoral Science Foundation(No.2022M712984)。
文摘Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.
基金supported by the National Natural Science Foundation of China(No.52061135101 and 52001078)the German Research Foundation(DFG,No.448318292)+3 种基金the Technology Innovation Guidance Special Foundation of Shaanxi Province(No.2023GXLH-085)the Fundamental Research Funds for the Central Universities(No.D5000240161)the Project of Key areas of innovation team in Shaanxi Province(No.2024RS-CXTD-20)The author Yingchun Xie thanks the support from the National Key R&D Program(No.2023YFE0108000).
文摘1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.
基金supported by the National Natural Science Foundation of China (NSFC) through Grant Number 42074193
文摘Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous quantitative analyses often simplified the chorus dispersion relation by using the cold plasma assumption.However,the applicability of the cold plasma assumption is doubtful,especially during geomagnetic disturbances.We here present a systematic statistical analysis on the validity of the cold plasma dispersion relation of chorus waves based on observations from the Van Allen Probes over the period from 2012 to 2018.The statistical results show that the observed magnetic field intensities deviate substantially from those calculated from the cold plasma dispersion relation and that they become more pronounced with an increase in geomagnetic activity or a decrease in background plasma density.The region with large deviations is mainly concentrated in the nightside and expands in both the radial and azimuthal directions as the geomagnetic activity increases or the background plasma density decreases.In addition,the bounce-averaged electron scattering rates are computed by using the observed and cold plasma dispersion relation of chorus waves.Compared with usage of the cold plasma dispersion relation,usage of the observed dispersion relation considerably lowers the minimum resonant energy of electrons and lowers the scattering rates of electrons above tens of kiloelectronvolts but enhances those below.Furthermore,these differences are more pronounced with the enhancement of geomagnetic activity or the decrease in background plasma density.
基金supported by the National Key Research and Development Program of China(No.2021YFB3701000)the National Natural Science Foundation of China(Nos.51971130,52201129,U21A2047,51821001,U2037601)+2 种基金support by the China Postdoctoral Science Foun-dation(2023M742219)the Postdoctoral Fellowship Program of CPSF under Grant Number GZB20240419support by the Ministry of Education,Singapore,under its Academic Research Fund Tier 2(MOE-T2EP50221-0013).
文摘Additive manufacturing (AM) of high-strength metallic alloys frequently encounters detrimental distortion and cracking, attributed to the accumulation of thermal stresses. These issues significantly impede the practical application of as-printed components. This study examines the Mg-15Gd-1Zn-0.4Zr (GZ151K, wt.%) alloy, a prototypical high-strength casting Mg-RE alloy, fabricated through laser powder bed fusion (LPBF). Despite achieving ultra-high strength, the GZ151K alloy concurrently exhibits a pronounced cold-cracking susceptibility. The as-printed GZ151K alloy consists of almost fully fine equiaxed grains with an average grain size of merely 2.87 µm. Subsequent direct aging (T5) heat treatment induces the formation of dense prismatic β' precipitates. Consequently, the LPBF-T5 GZ151K alloy manifests an ultra-high yield strength of 405 MPa, surpassing all previously reported yield strengths for Mg alloys fabricated via LPBF and even exceeding that of its extrusion-T5 counterpart. Interestingly, as-printed GZ151K samples with a build height of 2 mm exhibit no cracking, whereas samples with build heights ranging from 4 to 18 mm demonstrate severe cold cracking. Thermal stress simulation also suggests that the cold cracking susceptibility increases significantly with increasing build height. The combination of high thermal stress and low ductility in the as-printed GZ151K alloy culminates in a high cold cracking susceptibility. This study offers novel insights into the intricate issue of cold cracking in the LPBF process of high-strength Mg alloys, highlighting the critical balance between achieving high strength and mitigating cold cracking susceptibility.
基金funded by the Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0236)Fundamental Research Funds for the Central Universities(SWU-XDJH202308)Earmarked Funds for the China Agriculture Research System(CARS-26)。
文摘The complex of calcineurin B-like protein(CBL)and CBL-interacting protein kinase(CIPK)serves as key components in calcium-sensing,orchestrating various signals crucial for plant growth,development,and responses to biotic and abiotic stresses.However,the mechanism underlying the response of this module to cold stress and its role in flower development in wintersweet(Chimonanthus praecox)remains unclear.Through expression pattern analysis,calcium ion(Ca^(2+))concentration assays,correlation analysis,and linear regression analysis,we found that the[Ca^(2+)],along with CpCBL8 and CpCIPK9 expression levels in wintersweet flower buds(FBs),significantly decreased during the initial flowering stage when the chilling requirement reached 570 chill units(CU).Notably,there was a significant positive correlation between[Ca^(2+)]and CpCBL8 expression.Ca^(2+)increased the expression of Cp CBL8 and CpCIPK9 in FBs,causing a significant delay in the flowering of wintersweet.Furthermore,the function of CpCBL8 was studied using heterologous transformation.Overexpression of CpCBL8 significantly delayed flowering time and significantly reduced cold tolerance and altered the expression pattern of endogenous genes related to low-temperature stress and flower development in transgenic Arabidopsis thaliana.Additionally,transcriptome analysis of chilling-induced dormancy breaking and flower bud enlargement revealed that CpCBL8 and CpCIPK9 were negatively regulated by cold,and the expression pattern of endogenous genes related to flower development and cold stress in wintersweet were similar to that of in A.thaliana.Moreover,protein-protein interaction(PPI)analysis revealed that CpCBL8 and CpCIPK9 interacted in the plasma membrane and nucleus.On the basis of these findings,we speculated that the CpCBL8-CpCIPK9 module plays a crucial role in regulating responses to cold stress and flower development in wintersweet.This study elucidated molecular mechanisms through which the downregulation of the Ca^(2+)-induced CpCBL8-CpCIPK9 module results in dormancy breaking and enhances cold tolerance.This study provides valuable insights for the cultivation of new varieties of wintersweet with increased ornamental value and enhanced cold stress tolerance.
文摘A recent discovery in rice has revealed an elegant trick of nature:crops can teach their later generations to survive the cold through inherited memories written in chemical marks on the DNA letters,representing the first clear demonstration of what scientists call the“inheritance of acquired characteristics”-a phenomenon that biologists have debated for over two centuries.
基金supported from the Natural Science Foundation Project of Shanghai(Nos.23ZR1425300 and 22ZR1426100)Experimental Technical Team Construction Project of Shanghai Education Commission(No.10110N230080)+1 种基金National Natural Science Foundation of China(No.22075183)Research and Innovation Project of Shanghai Municipal Education Commission(No.2023ZKZD54).
文摘The addition of cold flow improvers(CFIs)is considered as the optimum strategy to improve the cold flow properties(CFPs)of diesel fuels,but this strategy is always limited by the required large dosage.To obtain low-dosage and high-efficiency CFIs for diesel,1,2,3,6-tetrahydrophthalic anhydride(THPA)was introduced as a third and polar monomer to enhance the depressive effects of alkyl methacrylatetrans anethole copolymers(C_(14)MC-TA).The terpolymers of alkyl methacrylate-trans anethole-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-TA-THPA)were synthesized and compared with the binary copolymers of C_(14)MC-TA and alkyl methacrylate-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-THPA).Results showed that C_(14)MC-THPA achieved the best depressive effects on the cold filter plugging point(CFPP)and solid point(SP)by 11℃and 16℃at a dosage of 1250 mg/L and monomer ratio of 6:1,while 1500mg/L C_(14)MC-TA(1:1)reached the optimal depressive effects on the CFPP and SP by 12℃and 18℃.THPA introduction significantly improved the depressive effects of C_(14)MC-TA.Lower dosages of C_(14)MCTA-THPA in diesel exerted better improvement effects on the CFPP and SP than that of C_(14)MC-TA and C_(14)MC-THPA.When the monomer ratio and dosage were 6:0.6:0.4 and 1000 mg/L,the improvement effect of C_(14)MC-TA-THPA on diesel reached the optimum level,and the CFPP and SP were reduced by 13℃and 19℃,respectively.A 3D nonlinear surface diagram fitted by a mathematical model was also used for the first time to better understand the relationships of monomer ratios,dosages,and depressive effects of CFIs in diesel.Surface analysis results showed that C_(14)MC-TA-THPA achieved the optimum depressive effects at a monomer ratio of 6:0.66:0.34 and dosage of 1000 mg/L,and the CFPP and SP decreased by 14℃ and 19℃,respectively.The predicted results were consistent with the actual ones.Additionally,the improvement mechanism of these copolymers in diesel was also explored.
文摘Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively analyzed from the aspects of circulation background,circulation situation,influence system,dynamic conditions,water vapor conditions,etc.The results show that the cold wave weather process appeared during the transition of circulation pattern from zonal to meridional type in middle and high latitudes in the northern Hemisphere.Due to the development of the European trough,the strong warm advection was transported to the Ural Ridge,making it strongly developed.The strong northerly wind belt in front of the ridge moved southwards.The warm advection at the rear of the transverse trough and the cold advection in the southeast in front of the transverse trough on the northwest side of Lake Baikal caused the transverse trough to turn upright and moved southwards,and the longitude of the circulation increased continuously to guide cold air to move southwards,resulting in this strong cold air process.The large ground pressure gradient caused by strong cold air and the frontogenesis of strong surface cyclone led to the gale in North China.
基金supported by National Natural Science Foundation of China(Nos.51806092,52201410)Non-Carbon Energy Conversion and Utilization Institute under the Shanghai Class IV Peak Disciplinary Development Program,High-End Foreign Experts Recruitment Plan of China(G2022013028L).
文摘Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was designed for cold storage applications.The optimal number of PCM plates was determined through numerical simulations to meet the required cold storage temperature and control time.Additionally,the air temperature field,flow field,and melting characteristics of the PCMplates during the cooling release process were analyzed.The effects of plate positioning and thickness on the cooling release performance were further investigated.The results indicated that when 64PCMplateswere used,the duration formaintaining temperatures below−18℃increased from0.6 h to approximately 16.94 h.During the cooling release process,the temperature field in the cold storage exhibited stratification,and the melting of the PCM plates was non-uniform.Placing the PCM plates at the top or within the interlayers without cargo above proved more effective,with their cooling release power being approximately twice that of the PCM plates placed in the interlayers with cargo above.Furthermore,reducing the thickness of the PCMplates from15 to 7.5mmresulted in a 3.6-h increase in the time below−18℃and a 4.5-h reduction in the time required to reach 80%liquid phase fraction.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(RS-2024-00451587)supported by Post-plastic Specialized Graduate Program through the Korea Environmental Industry&Technology Institute(KEITI)funded by the Ministry of Environment(MOE).
文摘Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibits a cold crystallization behavior.This abnormal behavior causes unstable mechanical properties at low-temperature and limits its applications in shape memory devices where crystallization is an essential mechanism.To analyze the unusual phenomenon,we compared different ether polyols focusing on symmetry characteristics and the evenodd effect of carbon backbones.It is found that PO3G has a slow crystallization rate because its ether linkages require specific chain arrangement for attractive interactions.Consequently,a thermal learning mechanism is developed to restore the normal crystallization behavior of elastomers synthesized from the bio-polyol.Repetitive heating and cooling cycles with high-temperature annealing induce urethane exchange reaction and reconstruct the chain orientations for fast crystallization.Results suggest the degree of crystallizations in polyurethane elastomer can be precisely controlled by introducing repetitive thermal treatments to enhance the potential applications of bio-polyols in polymer industries.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000300)the National Natural Science Foundation of China(Grant Nos.32272691 and 32025032)+1 种基金the Grape Breeding Project of Ningxia(Grant No.NXNYYZ202101-04)the Major Program of Technological Innovation in Hubei Province(Grant No.2022BBA0022)。
文摘Cold tolerance is one of the important traits for grapevine,especially in regions with extremely low temperatures in winter.Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared with Vitis vinifera.However,metabolites that contribute to the cold tolerance of V.amurensis remain unknown.Here,the metabolomics of buds from V.amurensis‘Zuoshan-1'during cold acclimation(CA)were identified,and cold-sensitive cultivar(V.vinifera‘Jingzaojing')was used as the control.The buds were collected in October,November,and December in 2016 and 2018.The cold hardiness of the buds increased during CA in the two grapevines.However,browning was observed only in V.vinifera buds at temperature below-10℃.Among detected metabolites from buds,443 metabolites were overlapped between two years.Forty-four and thirty differentially accumulated metabolites(DAMs)were identified in V.amurensis and V.vinifera,respectively.Ten DAMs including monoacylglycerol(MAG,18:2)isomer 1,trehalose 6-phosphate,and D-glucose showed identical variations in the two grapevines,indicating conserved CA responses within the Vitis genus.Eighteen DAMs exhibited higher accumulation in V.amurensis than in V.vinifera.Maltotetraose,D-glucoronic acid,L-aspartic acid,azelaic acid,and 4-hydroxybenzoic acid were reported to accumulate during CA in other plants.Enhanced cold tolerance was detected in grapevine leaves with exogenous 5 mmol L^(-1)L-aspartic acid and 1%proanthocyanidins.Potential contributions of other DAMs found in V.amurensis such as Cyanidin 3-O-glucoside need to be further elucidated.Thus,eighteen metabolites accumulated in V.amurensis can be used for practical application in improvement of cold resistance in grapevine.Our findings provide new insights into understanding the cold hardiness of V.amurensis.
基金funded by the Science and Technology Fundamental Resources Investigation Program of China(grant number 2017FY101201).
文摘Objective The role of cold spells of different intensities in the economic burden of death is crucial for health adaptation to climate change,especially in a multi-site setting.The objective of the study was to explore the economic burden of mortality attributable to cold spells Methods We performed a two-stage time-series analysis using the Value of Statistical Life(VSL)approach to evaluate the economic impact of mortality related to cold spells of varying lengths and intensities.This analysis employed a case-crossover design,with a distributed lag nonlinear model(DLNM)used for analysis.Analysis was stratified according to age,sex,and region of origin.The results of the assessment show that cold spells have an enormous impact on the economic losses of mortality due to climate change and aging.Results Totally,8.3%(95%CI:0.0%,16.0%)to 13.8%(95%CI:1.0%,24.8%)of VSL were ascribed to cold spells,accounting for economic losses of 4.71(95%CI:0.34,8.47)to 11.45(95%CI:0.00,21.00)billion CNY,in the cold season.The population aged over 65 y and females are particularly vulnerable.Economic impacts in warmer regions,such as the southern and subtropical zones,are more extensive than those in the northern and temperate zones.Conclusion Customizing cold spell prevention measures for vulnerable populations or regions is vital to alleviating the socioeconomic burden.
基金Supported by the National Natural Science Foundation of China (Nos.92158204,42176027,41876017,42076026)the project supported by Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2023SP240)+1 种基金the Open Research Project Program of the State Key Laboratory of Internet of Things for Smart City (University of Macao)(No.SKL-IoTSC (UM)-2021-2023/ORPF/A20/2022)the Postdoctoral Innovation Practice Base of Hezhu University and the Guangxi Yuchai New Energy Co.,Ltd.。
文摘The variations of the frontogenetic activity of cold filament driven by the different angle(θ=0°,22.5°,45°,67.5°,and 90°)of the wind and wave fields and the filament axis are studied by non hydrostatic large eddy simulation.Conversion between the frontogenesis and frontolysis of cold filament were created by the chang in the direction of secondary circulations.The changes in the direction of secondary circulation are induced by the Coriolis Effect regardless of wind direction and wave fields.The destructive action of the wind and wave fields on symmetry of the submesoscale flow fields becomes weak as the angle increases.The secondary downwelling jet induced by Stokes shear force is gradually close to that associated with secondary circulations as the angle changes fromθ=0°to 45°and then the downwelling jet is only created by secondary circulations forθ=67.5°and 90°.The frontogenetic intensity of cold filament may be impacted by the angle of the wind and wave fields and the filament axis.The reason is that firstly the odd-symmetry of secondary circulations enhances with the angle increasing,and secondary the secondary downwelling jet created the Stokes shear force gradually weakens and then disappears with the angle increasing.
基金supported by the Science and Technology Basic Resources Investigation Program of China(2019FY100500)the Fun-damental Research Funds for the Central Universities(2572023CT18)the Natural Fund Project of Heilongjiang Province(LH 2020C 044).
文摘In northern China,light and temperature are major limiting factors for plant growth,particularly during seed production and seedling establishment.While previous studies suggested a possible role for the MYB97 gene in cold-stress,confirmation through documented evidence was lacking.In this study,we transformed the MYB97 gene from Iris laevigata into tobacco,and discovered that the gene boosted photosynthesis,photoprotection and resilience to cold.The transgenic tobacco seeds exhibited enhanced germination and accelerated seedling growth.Moreover,these plants had decreased levels of MDA(Malondialdehyde)and relative conductance,coupled with elevated concentrations of proline and soluble sugars.This response was accompanied by heightened activity of antioxidant enzymes during periods of cold stress(4 and−2℃).Exposure to low temperatures(0–15℃)also reduced heights but accentuated primary root growth in transgenic tobacco plants.Additionally,tobacco leaves showed an increased growth along with higher chlorophyll levels,net photosynthetic rates,stomatal conductance,transpiration rates and non-photochemical quenching coefficient.This study shows that IlMYB97(The MYB97 genes in I.laevigata)improves cold-resistance,and enhances photosynthesis and photoprotective ability,and thus overall growth and development.These findings would offer the genetic resources to further study cold resistance and photosynthesis.
基金funded by Zhejiang Province Spearhead and Leading Goose Research and Development Key Program,grant number 2023C01239.
文摘In the realm of all-electric aircraft research,the integration of cathode-open proton exchange membrane fuel cells(PEMFC)with lithiumbatteries as a hybrid power source for small to medium-sized unmanned aerial vehicles(UAVs)has garnered significant attention.The PEMFC,serving as the primary energy supply,markedly extends the UAV’s operational endurance.However,due to payload limitations and spatial constraints in the airframe layout of UAVs,the stack requires customized adaptation.Moreover,the implementation of auxiliary systems to facilitate cold starts of the PEMFC under low-temperature conditions is not feasible.Relying solely on thermal insulation measures also proves inadequate to address the challenges posed by complex low-temperature startup scenarios.To overcomethis,our study leverages the UAV’s lithium battery to heat the cathode inlet airflow,aiding the cathode-open PEMFC cold start process.To validate the feasibility of the proposed air-assisted heating strategy during the conceptual design phase,this study develops a transient,non-isothermal 3Dcathode-open PEMF Cunitmodel incorporating cathode air-assisted heating and gas-ice phase change.The model’s accuracy was verified against experimental cold-start data from a stack composed of identical single cells.This computational framework enables quantitative analysis of temperature fields and ice fraction distributions across domains under varying air-assisted heating powers during cold starts.Building upon this model,the study further investigates the improvement in cold start performance by heating the cathode intake air with varying power levels.The results demonstrate that the fuel cell achieves self-startup at temperatures as low as−13℃ under a constant current density of 100mA/cm^(2) without air-assisted heating.At an ambient temperature of−20℃,a successful start-up can be achieved with a heating power of 0.45 W/cm^(2).The temperature variation overtime during the cold start process can be represented by a sum of two exponential functions.The air-assisted heating scheme proposed in this study has significantly improved the cold start performance of fuel cells in low-temperature environments.Additionally,it provides critical reference data and validation support for component selection and feasibility assessment of hybrid power systems.
基金supported by the National Natural Science Foundation of China(32130109 and 32373113)the National Natural Science Foundation of Shanghai(23ZR1426800)SciTech Funding by CSPFTZ Lingang Special Area Marine Biomedical Innovation Platform.
文摘Temperature fluctuations challenge ectothermic species,particularly tropical fish dependent on external temperatures for physiological regulation.However,the molecular mechanisms through which low-temperature stress impacts immune responses in these species,especially in relation to chromatin accessibility and epigenetic regulation,remain poorly understood.In this study,we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia(Oreochromis niloticus),a tropical fish of significant economic importance,under cold stress.By analyzing cis-regulatory elements in open chromatin regions and their associated transcription factors(TFs),we construct a comprehensive transcriptional regulatory network(TRN)governing immune responses,including DNA damage-induced apoptosis.Our analysis identifies 119 TFs within the TRN,with Stat1 emerging as a central hub exhibiting distinct binding dynamics under cold stress,as revealed by footprint analysis.Overexpression of Stat1 in immune cells leads to apoptosis and increases the expression of apoptosis-related genes,many of which contain Stat1-binding sites in their regulatory regions,emphasizing its critical role in immune cell survival during cold stress.These results provide insights into the transcriptional and epigenetic regulation of immune responses to cold stress in tilapia and highlight Stat1 as a promising target for enhancing cold tolerance in tropical fish species.
基金funded by the Health Commission of Heilongjiang Province(Project Number:20230808010517).
文摘Background:Cold temperatures cause blood vessels to constrict,shallow breathing,and slight thickening of the blood.Working in extremely cold environments can have negative effects on health,yet there are currently no effective biomarkers to monitor these health conditions.Proteins are important intermediate phenotypes that can provide a theoretical basis for understanding disease pathophysiology.Proteins in the circulatory system reflect the physiological status of individuals,and plasma proteins have significant potential as biomarkers for various health conditions.Methods:In this study,we employed the Mendelian randomization(MR)method to analyze the effects of freezing temperatures on over 2900 plasma proteins.Subsequently,the selected plasma proteins were subjected to causal analysis in relation to 55 diseases,including respiratory disorders,cardiovascular diseases,various cancers,and oral diseases.The aim was to identify proteins that could serve as biomarkers for health status.Results:Our results indicate that cold environments may affect the concentrations of 78 plasma proteins.Further MR analysis revealed that nine of these plasma proteins are associated with the risk of respiratory disorders,cardiovascular diseases,various cancers,and oral diseases.Conclusion:These proteins show promise as biomarkers for monitoring the hazards and risks faced by individuals working in cold environments.These findings provide valuable insights into the biological mechanisms underlying occupational hazards.
基金financial support from the Western Light Young Scholars Project,Chinese Academy of Sciences (2022)the Science and Technology Project of Sichuan Province,China (Project No.2021YFG0279)。
文摘Bioremediation is an efficient and popular approach for domestic wastewater treatment while the pollutant discharge standards are difficult to achieve under low-temperature conditions. The application of cold-resistant bacteria has gained increasing attention, but direct introduction to sewage leads to poor environmental adaptability and low microbial activity. Biochar was used as a carrier to immobilize the bacteria to improve microbial survival and activity in this study. The basic physicochemical properties of bacteria immobilized by biochar and ammonium nitrogen removal efficiency were analyzed. The process mechanism of ammonium nitrogen removal was further explored using kinetic fitting and molecular simulation calculations. The results showed that biochar immobilization of cold-resistant bacteria achieved a significantly higher ammonium nitrogen removal rate of 0.88 mg/(L·h) compared to free mixed bacteria(0.74 mg/(L·h)) and biochar alone(0.22 mg/(L·h)). It also exhibited a removal efficiency of 96.56%, which was 15.02% and 72.58% higher than that of free mixed bacteria and biochar, respectively. Adsorption kinetics further revealed that the pseudosecond-order kinetic equation was a better fit for characterizing ammonia-nitrogen removal by biocharimmobilized cold-resistant bacteria. Combining microscopic morphology analysis and molecular simulations demonstrated that enriching functional groups on biochar enhanced its NH_4~+ adsorption capacity by increasing surface activity and polarity, as well as the biodegradation ability of NH_4~+ by improving the interactions between biochar and active enzymes. These findings provide valuable insights into developing more effective ways to improve wastewater treatment efficiency under low temperatures.
基金supported by the Yantai Science and Technology Innovation Project(No.2023JCYJ097).
文摘The coastal regions of Laizhou Bay are highly susceptible to cold surges.This study used ERA5 reanalysis data from 2007 to 2022 and employed a hybrid model that integrates single-particle Lagrangian trajectories to statistically analyze the paths and intensity characteristics of cold surges in the Laizhou Bay area.Based on this analysis,a comparative analysis of outbreak processes,formation mechanisms,and causes of three different types of cold surge pathways was conducted.Results indicate variations in the characteristics of different cold surge pathways.Cold surges along the northern pathway originate from the Kara Sea.From a circula-tion perspective,the presence of a warm ridge over the Ural Mountains leads to the formation of a blocking system and an inverted‘Ω’flow pattern over Siberia.In contrast,cold surges along the northwest pathway originate from the Barents Sea,the Kara Sea,and the plains of Eastern Europe,with a pre-outbreak circulation displaying a characteristic‘ridge-trough-ridge’pattern.Finally,cold surges along the western pathway originate from the Norwegian Sea and the nearby plains of Eastern Europe,transitioning from a blocking pattern to a‘ridge-trough-ridge’pattern before the outbreak,distinguishing them from the northern and northwest path-ways.This research provides a basis for forecasting cold surge events in Laizhou Bay and for disaster prevention and mitigation in the coastal regions.
