In response to the actual demands of the energy storage type organic Rankine power generation cycle,this study proposes a new type of jacketed shell and tube heat exchanger with integrated cold storage and heat exchan...In response to the actual demands of the energy storage type organic Rankine power generation cycle,this study proposes a new type of jacketed shell and tube heat exchanger with integrated cold storage and heat exchange.N-tedecane is selected as the phase change material for cold storage,low-temperature water as the cold source,and R134a as the heat source.The phase change material for cold storage is filled inside the jacket tube of the heat exchanger.Cold fluid is introduced into the inner tube to cause the phase change material to condense and store cold.After the cold storage is completed,R134a flows in from the shell side and condenses through heat exchange with the solidified phase change material for energy storage.This study discusses the influence laws of different cold water mass flow rates and temperatures on the cold storage performance of this heat exchanger,and analyzes the condensation effect of R134a.The results show that when the mass flow rate is 0.5 kg/s and the cold water temperature is between 3 and 4℃,the average power of the energy storage heat exchanger in the condensation experiment is 80W,and the average convective heat transfer coefficient is 110.73 W/(m^(2)⋅K).This research provides an experimental basis for the development of energy storage organic Rankine power generation cycles.展开更多
As a specific spoilage organism of seafood under refrigerated temperature conditions,Shewanella spp.tend to form biofilms that exacerbate the occurrence of seafood spoilage.Biofilm-promoting factor A(BpfA)has been rep...As a specific spoilage organism of seafood under refrigerated temperature conditions,Shewanella spp.tend to form biofilms that exacerbate the occurrence of seafood spoilage.Biofilm-promoting factor A(BpfA)has been reported to promote the adhesion and biofilm formation of Shewanella spp.,but its role in adhesion and biofilm formation of S.putrefaciens under cold stress needs to be further investigated.To better comprehend the effect of BpfA on adhesion and biofilm formation of S.putrefaciens under cold stress(4℃),bacterial adhesion and biofilm phenotype of S.putrefaciens CN32 WT andΔbpfA at 4℃were analyzed and performed transcriptomics.The results showed that the deletion of bpfA had almost no effect on the growth of S.putrefaciens CN32 at 4℃,but weakened the unicellular adhesion capacity of S.putrefaciens CN32 and destabilized the stability of the multicellular adhesion layer.In addition,the biomass of the mature biofilm formed byΔbpfA was merely around 50%of that observed in the mature biofilm of S.putrefaciens CN32 WT,the average thickness and volume of the biofilm decreased by 18%and 27%,respectively,and the composition of the biofilm changed.Transcriptome analysis demonstrated that the deletion of bpfA led to differential expression of genes involved in metabolic pathways such as bacterial chemotaxis,two-component system,tyrosine metabolism,drug metabolism-other enzymes and biofilm formation-Vibrio cholerae,which in turn influenced bacterial adhesion and biofilm formation.Those results advance our acknowledgment of the character of BpfA on adhesion and biofilm formation of S.putrefaciens CN32,which contributes to understanding bacterial adhesion and the control of biofilm formation.展开更多
The cold chain environment is an important route for the long⁃distance transmission of pathogenic micro⁃organisms.In this study,we explored the mechanisms of secondary propagation through surface contact on cold surfa...The cold chain environment is an important route for the long⁃distance transmission of pathogenic micro⁃organisms.In this study,we explored the mechanisms of secondary propagation through surface contact on cold surfaces.A quantitative statistical experimental method was adopted to study the surface⁃contact transmission of micro⁃organisms,wherein the transfer rate of surface contact was the dependent variable and Escherichia coli was used as the indicator bacterium.The effects of contact pressure(0.44,0.86,1.55,2.25,and 2.94 N/cm^(2)),contact time(0,15,30,45,and 60 s),contact angle(15°and 25°),and surface materials(rubber and cotton gloves)were measured at two storage temperatures:cold storage(5℃)and freezing(-18℃).The results showed that as temperature decreases,the transfer of micro⁃organisms through surface contact becomes less probable.The contact time did not significantly influence the transfer rate of micro⁃organisms when items were handled at cold⁃storage temperatures.Based on these results,we recommend placing items as flat as possible to minimize the tilt angle when handling them at cold⁃storage temperatures.Additionally,if the tilt angle cannot be avoided,rubber gloves should be used when handling items stored at large tilt angles,whereas cotton gloves may be used for items placed at smaller angles.展开更多
As a large family of RNA helicases,DEAD-box(DDX)RNA helicases play crucial roles in almost all cellular RNA processing activities.However,the role of the DDX gene family in cold tolerance of mei(Prunus mume)remains un...As a large family of RNA helicases,DEAD-box(DDX)RNA helicases play crucial roles in almost all cellular RNA processing activities.However,the role of the DDX gene family in cold tolerance of mei(Prunus mume)remains unclear.In this study,we identified 45 DDX genes through whole-genome analysis unevenly distributed across eight chromosomes and scaffolds of mei.Based on the phylogenetic tree and gene structure analysis,the DDX genes were classified into nine subfamilies based on their motif compositions and intron-exon structures.The results of synteny analysis showed that segmental duplication was considered a major factor contributing to the amplification of the PmDDX family.RNA-Seq and qRT-PCR results revealed differential expression of PmDDX genes under cold stress.Among these,PmDDX39 was significantly up-regulated under cold stress,suggesting its positive role in modulating mei cold tolerance.We found that silenced PmDDX39 under cold stress led to greater damage than the wild seedlings via virus-induced gene silencing(VIGS).Conversely,overexpression of PmDDX39 in Arabidopsis enhanced cold stress tolerance.Moreover,dual luciferase and yeast one-hybrid(Y1H)demonstrated that PmDDX39 directly activates the expression of the C-repeat binding factor(PmCBFf)by binding to its promoters.This study provides new insights into the structure,evolution,and functional role of the PmDDX gene family in mei responses to cold stress.展开更多
The fabrication of 304L stainless welding wires with a diameter 1.6 mm by using electrochemical cold drawing(ECD)of bars with a diameter of 5.6 mm was investigated,as well as that via traditional cold drawing(TCD)for ...The fabrication of 304L stainless welding wires with a diameter 1.6 mm by using electrochemical cold drawing(ECD)of bars with a diameter of 5.6 mm was investigated,as well as that via traditional cold drawing(TCD)for comparison.The results indicated that the dilute H_(2)SO_(4)aqueous solution was an appropriate electrolyte for ECD,and increasing the H_(2)SO_(4)concentration and current density within a range improved the corrosion rate and uniformity,leading to an easier and more coordinated deformation through uniformly distributing geometrically necessary dislocations and curved large-angle grain boundaries,and decreasing their density,and thus,an enhanced electrochemical plasticization(EP).Under the optimized electrochemical parameters(0.5 mol L^(-1)H_(2)SO_(4)electrolyte and current density of 12.2 mA cm^(-2)),the average cumulative reduction rate required for annealing was up to~34%,obviously higher than~20%of TCD due to the decreased work-hardening from the EP,so that the number of annealing was significantly reduced from 10 of TCD to 5,when the drawing pass was 23.In addition,the surface of the ECD wire was distinctly smoother and brighter than that of the TCD one.These findings confirm the large potential in engineering applications of the ECD technology based on the EP effect.展开更多
The cold sintering process(CSP)is a green and innovative method of material densification at low temperatures(<350°C).The traditional CSP entails the addition of liquid phases as a solvent to achieve material ...The cold sintering process(CSP)is a green and innovative method of material densification at low temperatures(<350°C).The traditional CSP entails the addition of liquid phases as a solvent to achieve material densification through the dissolution-precipitation mechanism.However,it is difficult to realize for materials with low solubility.To address this challenge,a universal cold sintering method without the addition of liquid phases has been proposed in this work.The addition of a special polyester-polymer assisted the densification of insoluble ceramics,and hydroxyapatite(HA)and Al_(2)O_(3)were successfully sintered below 100°C,achieving 95-100%densities in a short time(5-20 min).This achievement can be attributed to the low glass transition temperature and the abundance of active sites(C=O)of the polyester-polymer.The denser ceramics exhibited enhanced mechanical properties,with the compression strength of polymer-assisted CSP HA increasing by 147.3%compared to the nanoparticles.Additionally,serving as an advanced bone substitute material,HA underwent quantitative analysis using the CCK-8 method and assessed the impact of polymer presence on cell proliferation and cytotoxicity.Meanwhile,a tight bonding between the polymer and ceramic materials was achieved during CSP,providing a generalized method for designing multifunctional ceramic-polymer.展开更多
A clear goal in cold tumor research is to identify strategies for converting them into immunologically‘hot’tumors with enhanced immune cell infiltration and activity,thereby improving their responsiveness to immunot...A clear goal in cold tumor research is to identify strategies for converting them into immunologically‘hot’tumors with enhanced immune cell infiltration and activity,thereby improving their responsiveness to immunotherapy.The genesis of cold tumors is exceedingly intricate.In recent times,as the analysis of this phenomenon has been pursued with greater depth,a suite of advanced diagnostic and therapeutic technologies has surfaced.These novel approaches and tactics are anticipated to modulate the tumor immune microenvironment across various dimensions,thereby facilitating the advancement of personalized and precise treatment modalities for cold tumors.The present article addresses the challenge of diminished therapeutic responsiveness to“cold tumors”within clinical settings.It systematically elucidates the multi-faceted regulatory mechanisms underlying immune evasion in cold tumors and offers a detailed analysis of advanced therapeutic strategies that incorporate nanotechnology,gene editing,and artificial intelligence methodologies.Furthermore,the future development trends of immunotherapy were explored in greater depth.It was posited that the convergence of artificial intelligence,multidimensional genomics,and emerging biotechnologies has presented positive prospects for the treatment of cold tumors,and has offered a theoretical foundation and technical framework for the transformation of cold tumors into“hot tumors”.展开更多
Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis t...Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis to examine the grain size characteristics of major riparian dunes in the typical cold and arid deserts of China.The results indicate that major riparian dunes of deserts in study area can be classified into three types based on their grain size characteristics.The Bartlett test of sphericity and the Kaiser-Meyer-Olkin(KMO)test were also performed,and their significance values were found to be 0.000 and 0.584,respectively.The results of the principal component analysis revealed that the cumulative contribution rate of the total variance reached 85.9%for the two principal components with characteristic roots greater than 1.0.The primary principal component included medium sand,whereas the secondary principal component included fine sand.We conducted a cluster analysis and classified the samples into three major types.Type I rivers include the Keriya River,Langqu River,Tora River and Heihe River,which are characterized by by fine particle size,and well-sorted.Type II includes Mu Bulag River,Kuye River,and the Xar Moron River,Compared with type I,it has a relatively coarser mean grain size and relatively poor sorting for this type.Type III includes the Maquan River,which is characterized mainly by fine sand and medium sand,accounting for more than 90%,and the sorting coefficient(0.52)suggests relatively well sorting in this pattern.Moreover,principal component analysis was applied to determine the particle sizes of samples from different watersheds.Moreover,these sediments exhibit both hydromorphic and aeolian features.At the drainage basin scale,the mode and intensity of aeolian-fluvial interactions depend on climatic conditions.In arid and semi-arid climate regions,wind is the dominant force,and the grain size exhibits significant aeolian features.Conversely,in the semi-humid region,flowing water is the dominant force,and riparian dunes in this region are formed by aeolian-fluvial interaction.The angle between the wind direction and flow direction in different reaches influences both the supply of sediment sources and the development of riparian dunes.This study will provide a new perspective for evaluating aeolian-fluvial interactions on riparian dunes in the deserts of China’s cold and arid regions.展开更多
Cold stress represents a critical constraint on crop productivity,particularly in temperate climates.Despite the established role of abscisic acid(ABA)in cold stress responses,the precise mechanisms through which tran...Cold stress represents a critical constraint on crop productivity,particularly in temperate climates.Despite the established role of abscisic acid(ABA)in cold stress responses,the precise mechanisms through which transcription factors mediate ABAdependent cold tolerance remain elusive.Here,we identify VaMYB4a,a MYB transcription factor from Vitis amurensis Rupr.(Amur grape),as a key regulator of cold tolerance.It integrates ABA signaling with the CBF(C-repeat binding factors)-COR(cold-regulated)pathway to orchestrate cold stress adaptation.Through a combination of overexpression and CRISPR/Cas9-mediated knockout lines in Arabidopsis thaliana,grape callus,and Vitis vinifera L.seedlings,we demonstrate that VaMYB4a enhances freezing tolerance by promoting osmotic regulation,reactive oxygen species(ROS)scavenging,and stomatal closure.VaMYB4a functions as a homo-dimer,with its C-terminal domain being essential for transcriptional activation.Mechanistically,VaMYB4a directly upregulates CBF and COR genes while fine-tuning ABA signaling components such as ABI1 and ABF4.Notably,ABA exhibits a dual role:enhancing VaMYB4a-mediated freezing tolerance under short-term stress but attenuating its effects during prolonged cold exposure,revealing an intricate regulatory crosstalk between cold and hormonal pathways.Our work not only advances the molecular understanding of cold adaptation but also provides a promising genetic target for developing stress-resilient grape varieties to mitigate the impacts of climate change.展开更多
The Northeast China Cold Vortex(NCCV)is a common cut-off low-pressure system in Northeast China,frequently causing localized heavy rainfall,strong winds,and thunderstorms during the early summer.In this study,the clea...The Northeast China Cold Vortex(NCCV)is a common cut-off low-pressure system in Northeast China,frequently causing localized heavy rainfall,strong winds,and thunderstorms during the early summer.In this study,the clear-sky radiance of 48 longwave channels from the FY-4B Geostationary Interferometric Infrared Sounder(GIIRS)is assimilated into the China Meteorological Administration mesoscale model(CMA-MESO)to evaluate its impact on NCCV development and its effects on rainfall forecasting.The results show that after assimilating the GIIRS radiance data,the warm center at 200 hPa and the cold center at 850 hPa of the NCCV are strengthened,and the dry intrusion at 850 hPa becomes more pronounced.This leads to a stronger NCCV intensity in the following 24 hours and brings the precipitation intensity and area closer to the observation,resulting in significant improvements compared to the experiments that do not assimilate GIIRS radiance data.Furthermore,it is found that the enhancement of the precipitation forecast is associated with the strengthening of cold air in the middle and lower troposphere,which intensifies the uplift of the warm,moist airflow.These results highlight the potential value of GIIRS data assimilation in enhancing early warnings and forecasts of extreme weather events influenced by the NCCV.展开更多
The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynam...The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynamics(MD)simulations,and other analytical techniques.The precipitation behavior during different aging stages of the supersaturated solid solution formed after rapid cold punching was focused,which induces rapid dissolution of precipitates.The findings reveal that the precipitation sequence is significantly influenced by aging temperature.At higher aging temperatures,which mitigate lattice distortion in the matrix,the precipitation sequence follows the conventional path.Conversely,at lower aging temperatures,where lattice distortion persists,the sequence deviates,suppressing the formation of Guinier−Preston−Bagaryatsky(GPB)zones.MD simulations confirm that the variations in solute atom diffusion rates at different aging temperatures lead to the differences in the S'phase precipitation sequence.展开更多
In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road perfor...In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road performance of emulsified asphalt cold recycled mixtures(ECRM),this study employed recycled asphalt pavement(RAP)and reclaimed inorganic binder stabilized aggregate(RAI)as dual recycled materials for ECRM preparation.The blending ratios of reclaimed base and surface layer mixtures significantly influence ECRM's performance,with adjusted proportions substantially improving compressive strength and dynamic modulus.Firstly,three distinct proportioning options were developed for the recycled materials.Mix designs incorporating varying RAP/RAI ratios were used to determine the optimal mix parameters:moisture content,cement dosage,and emulsified asphalt content.Subsequently,comprehensive performance evaluations were conducted through high-temperature wheel tracking tests,freeze-thaw splitting tests,uniaxial compression tests,and dynamic modulus measurements to analyze the pavement characteristics of the three ECRM formulations.Experimental results demonstrate:Compared with ECRM with a blending ratio of RAP:RAI:new aggregate=30:50:20(Option 1),the dynamic stability,freeze-thaw splitting strength ratio,compressive strength,and compressive resilient modulus of ECRM under Option 3(RAP:RAI:new aggregate=50:30:20)decreased by 31.8%,5.2%,16.4%,and 13.1%,respectively.This indicates that increasing RAP content while reducing RAI proportion enhances the tensile strength of ECRM,yet adversely affects its high-temperature stability,moisture resistance,and compressive performance.This work not only addresses the challenge of jointly utilizing asphalt pavement waste and base waste,but also provides a cost-effective and sustainable method for the stable application of milling material resources in road engineering.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
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
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
Thin walls of an AZ91 magnesium alloy with fine equiaxed grains were fabricated via cold arc-based wire arc additive manufacturing(CA-WAAM),and the droplet transfer behaviours,microstructures,and mechanical properties...Thin walls of an AZ91 magnesium alloy with fine equiaxed grains were fabricated via cold arc-based wire arc additive manufacturing(CA-WAAM),and the droplet transfer behaviours,microstructures,and mechanical properties were investigated.The results showed that the cold arc process reduced splashing at the moment of liquid bridge breakage and effectively shortened the droplet transfer period.The microstructures of the deposited samples exhibited layered characteristics with alternating distributions of coarse and fine grains.During layer-by-layer deposition,the β-phase precipitated and grew preferentially along grain boundaries,while the fineη-Al_(8)Mn_(5)phase was dispersed in the α-Mg matrix.The mechanical properties of the CA-WAAM deposited sample showed isotropic characteristics.The ultimate tensile strength and elongation in the building direction(BD)were 282.7 MPa and 14.2%,respectively.The microhardness values of the deposited parts were relatively uniform,with an average value of HV 69.6.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
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
基金the the basic scientific research Funds project of Heilongjiang Universities[grant numbers 2024-KYYWF-0554].
文摘In response to the actual demands of the energy storage type organic Rankine power generation cycle,this study proposes a new type of jacketed shell and tube heat exchanger with integrated cold storage and heat exchange.N-tedecane is selected as the phase change material for cold storage,low-temperature water as the cold source,and R134a as the heat source.The phase change material for cold storage is filled inside the jacket tube of the heat exchanger.Cold fluid is introduced into the inner tube to cause the phase change material to condense and store cold.After the cold storage is completed,R134a flows in from the shell side and condenses through heat exchange with the solidified phase change material for energy storage.This study discusses the influence laws of different cold water mass flow rates and temperatures on the cold storage performance of this heat exchanger,and analyzes the condensation effect of R134a.The results show that when the mass flow rate is 0.5 kg/s and the cold water temperature is between 3 and 4℃,the average power of the energy storage heat exchanger in the condensation experiment is 80W,and the average convective heat transfer coefficient is 110.73 W/(m^(2)⋅K).This research provides an experimental basis for the development of energy storage organic Rankine power generation cycles.
基金funded by the National Natural Science Foundation of China(32472401).
文摘As a specific spoilage organism of seafood under refrigerated temperature conditions,Shewanella spp.tend to form biofilms that exacerbate the occurrence of seafood spoilage.Biofilm-promoting factor A(BpfA)has been reported to promote the adhesion and biofilm formation of Shewanella spp.,but its role in adhesion and biofilm formation of S.putrefaciens under cold stress needs to be further investigated.To better comprehend the effect of BpfA on adhesion and biofilm formation of S.putrefaciens under cold stress(4℃),bacterial adhesion and biofilm phenotype of S.putrefaciens CN32 WT andΔbpfA at 4℃were analyzed and performed transcriptomics.The results showed that the deletion of bpfA had almost no effect on the growth of S.putrefaciens CN32 at 4℃,but weakened the unicellular adhesion capacity of S.putrefaciens CN32 and destabilized the stability of the multicellular adhesion layer.In addition,the biomass of the mature biofilm formed byΔbpfA was merely around 50%of that observed in the mature biofilm of S.putrefaciens CN32 WT,the average thickness and volume of the biofilm decreased by 18%and 27%,respectively,and the composition of the biofilm changed.Transcriptome analysis demonstrated that the deletion of bpfA led to differential expression of genes involved in metabolic pathways such as bacterial chemotaxis,two-component system,tyrosine metabolism,drug metabolism-other enzymes and biofilm formation-Vibrio cholerae,which in turn influenced bacterial adhesion and biofilm formation.Those results advance our acknowledgment of the character of BpfA on adhesion and biofilm formation of S.putrefaciens CN32,which contributes to understanding bacterial adhesion and the control of biofilm formation.
基金National Natural Science Foundation of China(Grant No.52278121).
文摘The cold chain environment is an important route for the long⁃distance transmission of pathogenic micro⁃organisms.In this study,we explored the mechanisms of secondary propagation through surface contact on cold surfaces.A quantitative statistical experimental method was adopted to study the surface⁃contact transmission of micro⁃organisms,wherein the transfer rate of surface contact was the dependent variable and Escherichia coli was used as the indicator bacterium.The effects of contact pressure(0.44,0.86,1.55,2.25,and 2.94 N/cm^(2)),contact time(0,15,30,45,and 60 s),contact angle(15°and 25°),and surface materials(rubber and cotton gloves)were measured at two storage temperatures:cold storage(5℃)and freezing(-18℃).The results showed that as temperature decreases,the transfer of micro⁃organisms through surface contact becomes less probable.The contact time did not significantly influence the transfer rate of micro⁃organisms when items were handled at cold⁃storage temperatures.Based on these results,we recommend placing items as flat as possible to minimize the tilt angle when handling them at cold⁃storage temperatures.Additionally,if the tilt angle cannot be avoided,rubber gloves should be used when handling items stored at large tilt angles,whereas cotton gloves may be used for items placed at smaller angles.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.QNTD202503)Forestry and Grassland Science and Technology Innovation Youth Top Talent Project of China(Grant No.2020132608)Beijing High-Precision Discipline Project,Discipline of Ecological Environment of Urban and Rural Human Settlements.
文摘As a large family of RNA helicases,DEAD-box(DDX)RNA helicases play crucial roles in almost all cellular RNA processing activities.However,the role of the DDX gene family in cold tolerance of mei(Prunus mume)remains unclear.In this study,we identified 45 DDX genes through whole-genome analysis unevenly distributed across eight chromosomes and scaffolds of mei.Based on the phylogenetic tree and gene structure analysis,the DDX genes were classified into nine subfamilies based on their motif compositions and intron-exon structures.The results of synteny analysis showed that segmental duplication was considered a major factor contributing to the amplification of the PmDDX family.RNA-Seq and qRT-PCR results revealed differential expression of PmDDX genes under cold stress.Among these,PmDDX39 was significantly up-regulated under cold stress,suggesting its positive role in modulating mei cold tolerance.We found that silenced PmDDX39 under cold stress led to greater damage than the wild seedlings via virus-induced gene silencing(VIGS).Conversely,overexpression of PmDDX39 in Arabidopsis enhanced cold stress tolerance.Moreover,dual luciferase and yeast one-hybrid(Y1H)demonstrated that PmDDX39 directly activates the expression of the C-repeat binding factor(PmCBFf)by binding to its promoters.This study provides new insights into the structure,evolution,and functional role of the PmDDX gene family in mei responses to cold stress.
基金supported by Major Science and Technology Project of Gansu Province(Grant No.23ZDGA010)National Natural Science Foundation of China(Grant No.51971105).
文摘The fabrication of 304L stainless welding wires with a diameter 1.6 mm by using electrochemical cold drawing(ECD)of bars with a diameter of 5.6 mm was investigated,as well as that via traditional cold drawing(TCD)for comparison.The results indicated that the dilute H_(2)SO_(4)aqueous solution was an appropriate electrolyte for ECD,and increasing the H_(2)SO_(4)concentration and current density within a range improved the corrosion rate and uniformity,leading to an easier and more coordinated deformation through uniformly distributing geometrically necessary dislocations and curved large-angle grain boundaries,and decreasing their density,and thus,an enhanced electrochemical plasticization(EP).Under the optimized electrochemical parameters(0.5 mol L^(-1)H_(2)SO_(4)electrolyte and current density of 12.2 mA cm^(-2)),the average cumulative reduction rate required for annealing was up to~34%,obviously higher than~20%of TCD due to the decreased work-hardening from the EP,so that the number of annealing was significantly reduced from 10 of TCD to 5,when the drawing pass was 23.In addition,the surface of the ECD wire was distinctly smoother and brighter than that of the TCD one.These findings confirm the large potential in engineering applications of the ECD technology based on the EP effect.
基金supported by the Jilin Provincial Natural Science Foundation(No.20240101118JC)the funds of Medical+X cross innovation team granted by medical department of Jilin University(No.2022JBGS07)+1 种基金the Jilin Province Science and Technology development project(No.20210101437JC)the WU JIEPING Medical Foundation(No.320.6750.2023-3-20 to TGM)。
文摘The cold sintering process(CSP)is a green and innovative method of material densification at low temperatures(<350°C).The traditional CSP entails the addition of liquid phases as a solvent to achieve material densification through the dissolution-precipitation mechanism.However,it is difficult to realize for materials with low solubility.To address this challenge,a universal cold sintering method without the addition of liquid phases has been proposed in this work.The addition of a special polyester-polymer assisted the densification of insoluble ceramics,and hydroxyapatite(HA)and Al_(2)O_(3)were successfully sintered below 100°C,achieving 95-100%densities in a short time(5-20 min).This achievement can be attributed to the low glass transition temperature and the abundance of active sites(C=O)of the polyester-polymer.The denser ceramics exhibited enhanced mechanical properties,with the compression strength of polymer-assisted CSP HA increasing by 147.3%compared to the nanoparticles.Additionally,serving as an advanced bone substitute material,HA underwent quantitative analysis using the CCK-8 method and assessed the impact of polymer presence on cell proliferation and cytotoxicity.Meanwhile,a tight bonding between the polymer and ceramic materials was achieved during CSP,providing a generalized method for designing multifunctional ceramic-polymer.
文摘A clear goal in cold tumor research is to identify strategies for converting them into immunologically‘hot’tumors with enhanced immune cell infiltration and activity,thereby improving their responsiveness to immunotherapy.The genesis of cold tumors is exceedingly intricate.In recent times,as the analysis of this phenomenon has been pursued with greater depth,a suite of advanced diagnostic and therapeutic technologies has surfaced.These novel approaches and tactics are anticipated to modulate the tumor immune microenvironment across various dimensions,thereby facilitating the advancement of personalized and precise treatment modalities for cold tumors.The present article addresses the challenge of diminished therapeutic responsiveness to“cold tumors”within clinical settings.It systematically elucidates the multi-faceted regulatory mechanisms underlying immune evasion in cold tumors and offers a detailed analysis of advanced therapeutic strategies that incorporate nanotechnology,gene editing,and artificial intelligence methodologies.Furthermore,the future development trends of immunotherapy were explored in greater depth.It was posited that the convergence of artificial intelligence,multidimensional genomics,and emerging biotechnologies has presented positive prospects for the treatment of cold tumors,and has offered a theoretical foundation and technical framework for the transformation of cold tumors into“hot tumors”.
基金Under the auspices of the General Project of Science and Technology Department of Shaanxi Province(No.2023-JCYB-264)General Program of National Natural Science Foundation of China(No.41801004,42371008,42471012)。
文摘Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis to examine the grain size characteristics of major riparian dunes in the typical cold and arid deserts of China.The results indicate that major riparian dunes of deserts in study area can be classified into three types based on their grain size characteristics.The Bartlett test of sphericity and the Kaiser-Meyer-Olkin(KMO)test were also performed,and their significance values were found to be 0.000 and 0.584,respectively.The results of the principal component analysis revealed that the cumulative contribution rate of the total variance reached 85.9%for the two principal components with characteristic roots greater than 1.0.The primary principal component included medium sand,whereas the secondary principal component included fine sand.We conducted a cluster analysis and classified the samples into three major types.Type I rivers include the Keriya River,Langqu River,Tora River and Heihe River,which are characterized by by fine particle size,and well-sorted.Type II includes Mu Bulag River,Kuye River,and the Xar Moron River,Compared with type I,it has a relatively coarser mean grain size and relatively poor sorting for this type.Type III includes the Maquan River,which is characterized mainly by fine sand and medium sand,accounting for more than 90%,and the sorting coefficient(0.52)suggests relatively well sorting in this pattern.Moreover,principal component analysis was applied to determine the particle sizes of samples from different watersheds.Moreover,these sediments exhibit both hydromorphic and aeolian features.At the drainage basin scale,the mode and intensity of aeolian-fluvial interactions depend on climatic conditions.In arid and semi-arid climate regions,wind is the dominant force,and the grain size exhibits significant aeolian features.Conversely,in the semi-humid region,flowing water is the dominant force,and riparian dunes in this region are formed by aeolian-fluvial interaction.The angle between the wind direction and flow direction in different reaches influences both the supply of sediment sources and the development of riparian dunes.This study will provide a new perspective for evaluating aeolian-fluvial interactions on riparian dunes in the deserts of China’s cold and arid regions.
基金supported by the Ningxia Hui Autonomous Region Key R&D Program,China(2023BCF01003)the National Natural Science Foundation of China(32472711 and 32060672)the Agricultural Breeding Project of Ningxia Hui Autonomous Region,China(NXNYYZ202101)。
文摘Cold stress represents a critical constraint on crop productivity,particularly in temperate climates.Despite the established role of abscisic acid(ABA)in cold stress responses,the precise mechanisms through which transcription factors mediate ABAdependent cold tolerance remain elusive.Here,we identify VaMYB4a,a MYB transcription factor from Vitis amurensis Rupr.(Amur grape),as a key regulator of cold tolerance.It integrates ABA signaling with the CBF(C-repeat binding factors)-COR(cold-regulated)pathway to orchestrate cold stress adaptation.Through a combination of overexpression and CRISPR/Cas9-mediated knockout lines in Arabidopsis thaliana,grape callus,and Vitis vinifera L.seedlings,we demonstrate that VaMYB4a enhances freezing tolerance by promoting osmotic regulation,reactive oxygen species(ROS)scavenging,and stomatal closure.VaMYB4a functions as a homo-dimer,with its C-terminal domain being essential for transcriptional activation.Mechanistically,VaMYB4a directly upregulates CBF and COR genes while fine-tuning ABA signaling components such as ABI1 and ABF4.Notably,ABA exhibits a dual role:enhancing VaMYB4a-mediated freezing tolerance under short-term stress but attenuating its effects during prolonged cold exposure,revealing an intricate regulatory crosstalk between cold and hormonal pathways.Our work not only advances the molecular understanding of cold adaptation but also provides a promising genetic target for developing stress-resilient grape varieties to mitigate the impacts of climate change.
基金sponsored by the National Natural Science Foundation of China(Grant No.42275171)the Basic Research Operating Expenses of the Institute of Meteorological Sciences,CMA(Grant No.2023Z019)+3 种基金the National Key Research and Development Program of China(Grant No.2022YFF0801304)the China Meteorological Administration Youth Innovation Team Fund(Grant No.CMA2024QN05)a Liaoning Provincial Meteorological Bureau Project(Grant No.D202201)Shenyang Institute of Atmospheric Environment Projects(Grant Nos.2022SYIAEJY13 and 2018SYIAEZD5).
文摘The Northeast China Cold Vortex(NCCV)is a common cut-off low-pressure system in Northeast China,frequently causing localized heavy rainfall,strong winds,and thunderstorms during the early summer.In this study,the clear-sky radiance of 48 longwave channels from the FY-4B Geostationary Interferometric Infrared Sounder(GIIRS)is assimilated into the China Meteorological Administration mesoscale model(CMA-MESO)to evaluate its impact on NCCV development and its effects on rainfall forecasting.The results show that after assimilating the GIIRS radiance data,the warm center at 200 hPa and the cold center at 850 hPa of the NCCV are strengthened,and the dry intrusion at 850 hPa becomes more pronounced.This leads to a stronger NCCV intensity in the following 24 hours and brings the precipitation intensity and area closer to the observation,resulting in significant improvements compared to the experiments that do not assimilate GIIRS radiance data.Furthermore,it is found that the enhancement of the precipitation forecast is associated with the strengthening of cold air in the middle and lower troposphere,which intensifies the uplift of the warm,moist airflow.These results highlight the potential value of GIIRS data assimilation in enhancing early warnings and forecasts of extreme weather events influenced by the NCCV.
基金supported by the China Scholarship Council (CSC) Local Cooperation Program (No. 202308430176)the National Natural Science Foundation of China (No. 52271177)the Hunan Provincial Natural Science Foundation Regional Joint Fund, China (No. 2023JJ50173)。
文摘The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynamics(MD)simulations,and other analytical techniques.The precipitation behavior during different aging stages of the supersaturated solid solution formed after rapid cold punching was focused,which induces rapid dissolution of precipitates.The findings reveal that the precipitation sequence is significantly influenced by aging temperature.At higher aging temperatures,which mitigate lattice distortion in the matrix,the precipitation sequence follows the conventional path.Conversely,at lower aging temperatures,where lattice distortion persists,the sequence deviates,suppressing the formation of Guinier−Preston−Bagaryatsky(GPB)zones.MD simulations confirm that the variations in solute atom diffusion rates at different aging temperatures lead to the differences in the S'phase precipitation sequence.
基金sponsored by National Natural Science Foundation of China(No.52308466)SASAC Science and Technology Innovation Project(JF-23-01-0063)Shaanxi Provincial Transportation Research Project(25-84 K,25-85 K).
文摘In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road performance of emulsified asphalt cold recycled mixtures(ECRM),this study employed recycled asphalt pavement(RAP)and reclaimed inorganic binder stabilized aggregate(RAI)as dual recycled materials for ECRM preparation.The blending ratios of reclaimed base and surface layer mixtures significantly influence ECRM's performance,with adjusted proportions substantially improving compressive strength and dynamic modulus.Firstly,three distinct proportioning options were developed for the recycled materials.Mix designs incorporating varying RAP/RAI ratios were used to determine the optimal mix parameters:moisture content,cement dosage,and emulsified asphalt content.Subsequently,comprehensive performance evaluations were conducted through high-temperature wheel tracking tests,freeze-thaw splitting tests,uniaxial compression tests,and dynamic modulus measurements to analyze the pavement characteristics of the three ECRM formulations.Experimental results demonstrate:Compared with ECRM with a blending ratio of RAP:RAI:new aggregate=30:50:20(Option 1),the dynamic stability,freeze-thaw splitting strength ratio,compressive strength,and compressive resilient modulus of ECRM under Option 3(RAP:RAI:new aggregate=50:30:20)decreased by 31.8%,5.2%,16.4%,and 13.1%,respectively.This indicates that increasing RAP content while reducing RAI proportion enhances the tensile strength of ECRM,yet adversely affects its high-temperature stability,moisture resistance,and compressive performance.This work not only addresses the challenge of jointly utilizing asphalt pavement waste and base waste,but also provides a cost-effective and sustainable method for the stable application of milling material resources in road engineering.
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.
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 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(No.51805265)the Fundamental Research Funds for the Central Universities,China(No.30922010921).
文摘Thin walls of an AZ91 magnesium alloy with fine equiaxed grains were fabricated via cold arc-based wire arc additive manufacturing(CA-WAAM),and the droplet transfer behaviours,microstructures,and mechanical properties were investigated.The results showed that the cold arc process reduced splashing at the moment of liquid bridge breakage and effectively shortened the droplet transfer period.The microstructures of the deposited samples exhibited layered characteristics with alternating distributions of coarse and fine grains.During layer-by-layer deposition,the β-phase precipitated and grew preferentially along grain boundaries,while the fineη-Al_(8)Mn_(5)phase was dispersed in the α-Mg matrix.The mechanical properties of the CA-WAAM deposited sample showed isotropic characteristics.The ultimate tensile strength and elongation in the building direction(BD)were 282.7 MPa and 14.2%,respectively.The microhardness values of the deposited parts were relatively uniform,with an average value of HV 69.6.
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 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.
