Near-eutectic Al-Si alloys are widely used in automotive manufacturing due to their superior wear resistance and high temperature *** of high Si content,the grain refinement of near-eutectic Al-Si alloy has been a pro...
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Near-eutectic Al-Si alloys are widely used in automotive manufacturing due to their superior wear resistance and high temperature *** of high Si content,the grain refinement of near-eutectic Al-Si alloy has been a problem for many *** this study,the effect of deep cryogenic treatment(DCT)on the microstructure and mechanical properties of Al-12Si-4Cu-2Ni-mg alloy with addition of Al-Ti-C-B master alloy was fully *** show that the average grain size of the alloy is greatly reduced from 0.92 mm to 0.50 mm,and the eutectic Si and Al7Cu4Ni precipitates are spheroidized and refined in Al-12Si-4Cu-2Ni-mg after DCT for 24 h and aging *** these changes of microstructures result in a significant increment of about 22.5%in elongation and a slight enhancement of about 6.8%in tensile ***,the refinement of microstructure also significantly improves the fatigue life of the alloy.
The development of flexible supercapacitors(FSCs) capable of operating at high temperatures is crucial for expanding the application areas and operating conditions of supercapacitors. Gel polymer electrolytes and elec...
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The development of flexible supercapacitors(FSCs) capable of operating at high temperatures is crucial for expanding the application areas and operating conditions of supercapacitors. Gel polymer electrolytes and electrode materials stand as two key components that significantly impact the efficacy of hightemperature-tolerant FSCs(HT-FSCs). They should not only exhibit high electrochemical performance and excellent flexibility, but also withstand intense thermal stress. Considerable efforts have been devoted to enhancing their thermal stability while maintaining high electrochemical and mechanical performance. In this review, the fundamentals of HT-FSCs are outlined. A comprehensive overview of state-of-the-art progress and achievements in HT-FSCs, with a focus on thermally stable gel polymer electrolytes and electrode materials is provided. Finally, challenges and future perspectives regarding HT-FSCs are discussed, alongside strategies for elevating operational temperatures and *** review offers both theoretical foundations and practical guidelines for designing and manufacturing HT-FSCs, further promoting their widespread adoption across diverse fields.
Saltmarsh is one of the blue carbon ecosystems for the highest carbon burial ***,the buried carbon in saltmarsh may still be exported to coastal water through porewater exchange,a process that has often been overlooke...
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Saltmarsh is one of the blue carbon ecosystems for the highest carbon burial ***,the buried carbon in saltmarsh may still be exported to coastal water through porewater exchange,a process that has often been overlooked in previous studies.A typical tidal creek of the Dongtan saltmarsh wetland in Chongming Island,Shanghai,China,was ***224Ra and223Ra activities were measured and the hydrological parameters such as water flow were determined,from which the porewater exchange rate in the tidal creek was estimated to be 1.78±1.73 cm/***,the carbon concentrations in porewater were determined,based on which the fluxes of dissolved inorganic carbon(DIC),dissolved organic carbon(DOC),CH_(4),and CO_(2)exported from porewater exchange were derived to be 60±17,6.6±4.0,0.082±0.079,and 16±11 mmol/(m^(2)·d),*** addition,analysis on different species of carbon in the creek water showed that,the fluxes of DIC,DOC,CH_(4),and CO_(2)exported laterally from tidal creek to coastal sea were 58±14,7.6±2.3,0.0011±0.00063,and 1.5±0.68 mmol/(m^(2)·d),respectively,indicating that the porewater exchange-derived carbon fluxes accounted for a large portion of the lateral carbon outwelling,and even much higher than those in CH_(4)and CO_(2)***,the carbon exported from porewater exchange accounted for 50%of the carbon burial in the tidal creek system,of which DIC accounted for 73%of the total carbon flux transported by porewater ***,this study indicated that the porewater exchange-derived carbon fluxes to the tidal creek water may cause an overestimation in the carbon sequestration capacity of saltmarsh wetlands,and revealed the importance of porewater exchange for the carbon cycle of tidal creek system of saltmarsh wetlands.
Aqueous zinc-ion batteries encounter enormous challenges such as Zn dendrites and parasitic *** modification is a highly effective strategy to address these *** the advantages of low cost,nontoxicity,biodegradability,...
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Aqueous zinc-ion batteries encounter enormous challenges such as Zn dendrites and parasitic *** modification is a highly effective strategy to address these *** the advantages of low cost,nontoxicity,biodegradability,good film-forming ability,superior hydro phi licity,and rich functional groups,chitosan is an ideal matrix for constructing ***,the presence of positive charges within chitosan in weakly acidic electrolytes is unfavorable for dendrite ***,Schiff base reaction is introduced to modify chitosan matrix,transforming its charge polarity from positive to ***,NbN with excellent zincophilicity is coated onto chitosan matrix,forming a Janus separator with low thickness of 19 μm and considerably improved mechanical *** resultant separator can promote the transport of Zn2+ions while triggering a repulsive shielding effect against anions,therefore dramatically enhancing Zn2+ion transfer number from 0.28 to *** separator can also facilitate desolvation process,improve exchange current density,restrict two-dimensional Zn2+ion diffusion,and enhance electrochemical kinetics,contributing to significantly inhibited dendrite growth,by-product formation,and hydrogen ***,stable and reversible Zn stripping/plating process is enabled for over 2500 h at 2 mA cm-2and 2 mAh *** great rate capability and excellent cyclability can be achieved for full batteries even under harsh *** work provides new insights into separator design for Zn-based batteries.
Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature ...
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Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature treatment were conducted with a ϕ75 mm split Hopkinson tension bar (SHTB) to investigate the mesoscopic fracture and damage properties of rock. An improved scanning electron microscopy (SEm) experimental method was used to analyze the tensile fracture surfaces of rock samples. Qualitative and quantitative analyses were performed to assess evolution of mesoscopic damage of heat-damaged rock under tensile loading. A constitutive model describing the mesoscopic fractal damage under thermo-mechanical coupling was established. The results showed that the high temperatures significantly reduced the tensile strength and fracture surface roughness of the red sandstone. The three-dimensional (3D) reconstruction of the fracture surface of the samples that experienced tensile failure at 900 °C showed a flat surface. The standard deviation of elevation and slope angle of specimen fracture surface first increased and then decreased with increasing temperature. The threshold for brittle fracture of the heat-damaged red sandstone specimens was 600 °C. Beyond this threshold temperature, local ductile fracture occurred, resulting in plastic deformation of the fracture surface during tensile fracturing. With increase of temperature, the internal meso-structure of samples was strengthened slightly at first and then deteriorated gradually, which was consistent with the change of macroscopic mechanical properties of red sandstone. The mesoscopic characteristics, such as the number, mean side length, maximum area, porosity, and fractal dimension of crack, exhibited an initial decline, followed by a gradual increase. The development of microcracks in samples had significant influence on mesoscopic fractal dimension. The mesoscopic fractal characteristics were used to establis
The results of experimental research of multi-injector combustors in the regime of the attached pipe are *** a source of high-enthalpy working gas (air), hot shot wind tunnel IT-302m of ITAm, the Siberian Branch ofthe...
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The results of experimental research of multi-injector combustors in the regime of the attached pipe are *** a source of high-enthalpy working gas (air), hot shot wind tunnel IT-302m of ITAm, the Siberian Branch ofthe Russian Academy of Sciences was used. Tests have been carried out at mach numbers 3,4 and 5, in a range ofchange of total temperature from 2000K up to 3000K and static pressure from 0.08mPa up to 0.23mPa. Injectorsection has been manufactured in two versions with a various relative height of wedge-shaped injectors with parallelfuel injection. Influence of conditions on the entrance of the combustion chamber on ignition and a stablecombustion of hydrogen was investigated. Intensive combustion of hydrogen has been received only at machnumbers 3 and 4. Advantage of injector section with the greater relative height of injectors is revealed. Themechanism of fuel ignition in the combustion chamber of the given configuration was investigated: two-step ignitionprocess including 'kindling' and intensive combustion over all channel volume.
The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider(RHIC)at Brookhaven National Laboratory(BNL).It provides a unique opportunity to probe the c...
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The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider(RHIC)at Brookhaven National Laboratory(BNL).It provides a unique opportunity to probe the correlation between the po-larized quark and antiquark in the strongly coupled quark-gluon plasma(sQGP)produced in relativistic heavy ion collisions,opening a new window to explore the properties of *** addition,spin alignments of vector mesons have also been observed in other high-energy particle collisions such as e^(+)e^(−)annihilations at high energies where hadron production is dominated by quark fragmentation *** results obtained are quite different from those obtained in heavy ion collisions where quark coalescence/combination mechanism dominates suggesting strong dependence on hadronization *** comprehensive studies in different hadronization processes are *** this article,we present a brief review of theoretical and experimen-tal advances in the study of vector meson’s spin alignments in a variety of high-energy particle collisions,with emphasis on hadronization mechanisms.
The development of alkaline fuel cells is moving forward at an accelerated pace,and the application of ether-free bonded polymers to anion exchange membranes(AEms)has been widely ***,the question of the“trade-off”be...
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The development of alkaline fuel cells is moving forward at an accelerated pace,and the application of ether-free bonded polymers to anion exchange membranes(AEms)has been widely ***,the question of the“trade-off”between AEm ionic conductivity and dimensional stability remains *** strategy of inducing microphase separation to improve the performance of AEm has attracted much attention recently,but the design of optimal molecular structures is still being ***,this work introduced different ratios of 3-bromo-1,1,1-trifluoroacetone(x=40,50,and 60)into the main chain of poly(p-terphenylene isatin).Because fluorinated groups have excellent hydrophobicity,hydrophilic hydroxyl-containing side chains are introduced to jointly adjust the formation of phase separation *** results show that PTI-PTF_(50)-NOH AEm with the appropriate fluorinated group ratio has the best ionic conductivity and alkali stability under the combined effect of *** has an ionic conductivity of 133.83 mS cm^(-1)at 80°*** addition,the OH-conductivity remains at 89%of the initial value at 80°C and 3 m KOH for 1056 h of *** cell polarization curve based on PTI-PTF_(50)-NOH shows a power density of 734.76 mW cm^(-2)at a current density of 1807.7 mA cm^(-2).
Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial rol...
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Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial role played by gravel in the ecological restoration of these *** study utilizes supervised classification and segmentation techniques based on machine learning to extract gravel morphology profiles from field-sampled plot images and calculate their characteristic *** a multivariate linear approach combined with Principal Component Analysis(PCA),a model for inferring gravel characteristic parameters is *** features,particle size characteristics,and spatial distribution patterns of gravel are *** reveal that gravel predominantly exhibit sub-rounded shapes,with 80%classified as fine *** coefficients of determination(R2)between gravel particle size and coverage,perimeter,and area are 0.444,0.724,and 0.557,respectively,indicating linear *** cumulative contribution rate of the top five remote sensing factors is 95.44%,with the first geological factor contributing 77.64%,collectively reflecting the primary information of the 20 factors *** shows that areas with larger gravel particle sizes correspond to increased perimeter and *** in the Nagqu Prefecture of northern Tibet have a particle size range of 4-8 mm,primarily comprising fine gravel which accounts for 94.61%.These findings provide a scientific basis for extracting gravel characteristic parameters and understanding their spatial distribution variations in the northern Tibetan Plateau.
Due to the significant impact of carbon dioxide on global ecology,more efforts have been put into the exploration on CO2capture and *** organic framework materials,as a kind of materials with high porosity and designa...
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Due to the significant impact of carbon dioxide on global ecology,more efforts have been put into the exploration on CO2capture and *** organic framework materials,as a kind of materials with high porosity and designable structure,have been considered as effective host materials for adsorbing carbon dioxide or separating it from other *** review gives a deep insight into the applications of metal-organic frameworks,covalent-organic frameworks,and other porous frameworks on CO2capture,focusing on the enhanced capture performances originated from their high surface area with abundant porous structure,functional groups with specific heteroatoms modification,or other building unit ***,the main challenges associated with porous frameworks for CO2capture and proposed strategies to address these obstacles,including the structural design strategy or the capture mechanism exploration,have been demonstrated and *** review can contribute to further investigation on porous frameworks for gas capture and separation with enhanced performance and efficiency.
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