The International STEM Education Forum in Suzhouopened in Soochow University on May 30, attractingscholars and experts in STEM education and cultivatingtechnology talents from home and abroad.Under the guidance of Dep...The International STEM Education Forum in Suzhouopened in Soochow University on May 30, attractingscholars and experts in STEM education and cultivatingtechnology talents from home and abroad.Under the guidance of Department of Foreign ExpertsServices, Ministry of Science and Technology(MOST ), the event was jointly organized by ForeignTalent Research Center,Ministry of Science and Technologyand China Guanghua Foundation.展开更多
AIM:To investigate the pathogenesis of biliary casts after liver transplantation relative to their morphology and biochemical markers.METHODS:The microstructure of biliary casts was assessed using scanning electron mi...AIM:To investigate the pathogenesis of biliary casts after liver transplantation relative to their morphology and biochemical markers.METHODS:The microstructure of biliary casts was assessed using scanning electron microscopy and Hematoxylin and eosin staining assessed their histology.The expression levels of CD3,CD5,CD34,CD68 and CD79a in these biliary casts were evaluated immunohistochemically.RESULTS:Biliary casts differed widely in their microstructure,with some containing blood vessels positive for CD34 and collagen fibers with positive Masson staining.Large numbers of neutrophils and other inflammatory cells were present,but only on the edge of the biliary casts;although the boundaries were clear without crossover.None of the biliary casts contained T-lymphocytes,B-lymphocytes,macrophages and other inflammatory cells.CONCLUSION:The microcostructure of biliary casts differed.Bacteria and acute rejection are not clearly related to their formation.展开更多
Objective: This study presents the microvasculature of the horse iris, ciliary process, retina, and choroid and discusses the functional significance of the vasculature. Procedure: Seven horses were used for this stud...Objective: This study presents the microvasculature of the horse iris, ciliary process, retina, and choroid and discusses the functional significance of the vasculature. Procedure: Seven horses were used for this study. The ocular vascular system was injected with methylmethacrylate resin via the carotid artery, and the vascular corrosion casts were observed using a scanning electron microscope. Results: The iridial vessels showed a wavy course. The ciliary process was supplied by 2 arterial routes: the iridial and ciliary arterial circles. The subjects displayed a paurangiotic retina with retinal vessels extending only a short distance around the disc. The retinal arterioles and venules ran in closely related pairs, and the capillaries formed hairpin loops. No central retinal artery was seen in the equine eyes examined. The choriocapillaris in the avascular retina was arranged in honeycomb hexagon lobules and formed a more densely packed network than that in the vascular retina. There were 2 distinct venous drainage systems in the horse choroid: the vortex veins and the posterior ciliary veins. The vortex vein ampulla was flattened and showed a slit-like lumen at the merge site with the ophthalmic vein. The vortex veins demonstrated a marked constriction before leaving the eye. Discussion: The 2 choroidal drainage systems may compensate each other in event of occlusion. The ampulla and the constriction in the vortex veins may act as a valve regulating the blood flow to keep the eye at an optimum size and the intraocular pressure within the normal physiological range.展开更多
Effects of earthworm casts on soil nutrient dynamics and their responses to changing moisture availability in subtropical ecosystems remain poorly understood.This study aimed to examine short-term carbon(C)and nitroge...Effects of earthworm casts on soil nutrient dynamics and their responses to changing moisture availability in subtropical ecosystems remain poorly understood.This study aimed to examine short-term carbon(C)and nitrogen(N)dynamics and their interactions with wetting-drying cycles in three different structural forms(i.e.,granular,globular,and heap-like)of Amynthas earthworm casts.The rates of C and N mineralization in the earthworm casts were examined under two different wetting-drying cycles(i.e.,2-d and 4-d wetting intervals)using a rainfall simulation experiment.After three simulated rainfall events,subsamples of the earthworm casts were further incubated for 4 d for the determination of CO2 and N2O fluxes.The results of this study indicated that the impacts of wetting-drying cycles on the short-term C and N dynamics were highly variable among the three cast forms,but wetting-drying cycles significantly reduced the cumulative CO2 and N2O fluxes by 62%-83%and 57%-85%,respectively,when compared to the control without being subjected to any rainfall events.The C mineralization rates in different cast forms were affected by the amount of organic substrates and N content in casts,which were associated with the food preference and selection of earthworms.Meanwhile,the cumulative N2O fluxes did not differ among the three cast forms.Repeated wetting and drying of casts not only enhanced aggregate stability by promoting bonds between the cast particles,but also inhibited microbial survival and growth during the prolonged drying period,which together hindered decomposition and denitrification.Our findings demonstrated that the interactions between the structural forms,aggregate dynamics,and C and N cycling in the earthworm casts were highly complex.展开更多
AIM To determine if complete, split casts and backslabs [plaster of Paris(POP) and fiberglass] generate different intracast pressures and pain. METHODS Increased swelling within casts was modeled by a closed water sys...AIM To determine if complete, split casts and backslabs [plaster of Paris(POP) and fiberglass] generate different intracast pressures and pain. METHODS Increased swelling within casts was modeled by a closed water system attached to an expandable bag placed directly under different types of casts applied to a healthy lower limb. Complete fiberglass and POP casts, split casts and backslabs were applied. Twenty-five milliliter aliquots of saline were injected into the system and the generated intracast pressures were measured using a sphygmomanometer. The subject was blinded to the pressure scores to avoid bias. All casts were applied to the same right limb on the same subject to avoid the effects of variations in anatomy or physiology on intracast pressures. Pain levels were evaluated using the Visual Analogue Score after each sequential saline injection. Each type of cast was reapplied four times and the measurements were repeated on four separate occasions. Sample sizes were determined by a pre-study 90% power calculation to detect a 20% difference in intracast pressures between cast groups. RESULTS A significant difference between the various types of casts was noted when the saline volume was greater than 100 mL(P = 0.009). The greatest intracast pressure was generated by complete fiberglass casts, which were significantly higher than complete POP casts or backslabs(P = 0.018 and P = 0.008 respectively) at intracast saline volumes of 100 mL and higher. Backslabs produced a significantly lower intracast pressure compared to complete POP only once the saline volume within casts exceeded 225 mL(P = 0.009). Intracast pressures were significantly lower in split casts(P = 0.003). Split POP and fiberglass casts produced the lowest intracast pressures, even compared to backslabs(P = 0.009). Complete fiberglass casts generated the highest pain levels at manometer pressures of 75 mm Hg and greater(P = 0.001). Split fiberglass casts had significantly reduced pain levels(P = 0.001). In contrast, a split complete POP cast did not produce significantly reduced pain levels at pressures between 25-150 mmH g. There was no difference in pain generated by complete POP and backslabs at manometer pressures of 200 mm Hg and lower. CONCLUSION Fibreglass casts generate significantly higher intracast pressures and pain than POP casts. Split casts cause lower intracast pressures regardless of material, than complete casts and backslabs.展开更多
The internal cracks in continuously cast slabs are attributed to the excessive tensile strain occurring at the solidifying frontduring the continuous casting process. Based on the understanding, a model for diagnosing...The internal cracks in continuously cast slabs are attributed to the excessive tensile strain occurring at the solidifying frontduring the continuous casting process. Based on the understanding, a model for diagnosing the formation of the internal cracks was established, in which the strains at the solidifying front caused by' bulging, straightening or unbending, and roll misalignment were calculated and compared with a critical strain value to estimate whether the internal cracks form. Moreover, the established model was appliedto a real slab caster to reveal the distribution of the strains in casting direction and its effect on the internal cracks. It was proved that themodel was reliable and useful for optimizing the operation of continuous casting.展开更多
Purpose:Secondary displacement represents a frequent complication of conservative treatment of fractures,particularly of the distal radius.The gap space between skin and cast may lead to a certain degree movements and...Purpose:Secondary displacement represents a frequent complication of conservative treatment of fractures,particularly of the distal radius.The gap space between skin and cast may lead to a certain degree movements and this increased mobility might favor redisplacement.The aim of this study was to develop a new 3D method,to measure the gap space in all 3 geometrical planes,and to validate this new technique in a clinical setting of distal radius fractures.Methods:This study applies 3D imaging to measure the space between plaster and skin as a potential factor of secondary displacement and therefore the failure of conservative treatment.We developed and validated a new methodology to analyze and compare different forearm casts made of plaster of Paris and fiberglass.An unpaired t-test was performed to document differences between the investigated parameters between plaster of Paris and fiberglass casts.The significance level was set at p<0.05.Results:In a series of 15 cases,we found the width of the gap space to average 4 mm,being slightly inferior on the radial side.Comparing the two different casting materials,plaster of Paris and fiberglass,we found a significantly larger variance of space under casts made of the first material(p=0.39).A roughness analysis showed also a markedly significantly higher irregularity of the undersurface of plaster of Paris as compared with fiberglass.Conclusion:This study allows for a better understanding of the nature of the"gap space"between cast and skin and will contribute to develop and improve new immobilization techniques and materials.展开更多
Cone-beam computed tomography(CBCT),a modern technique with many applications,is becoming increasingly important and essential in many areas of economics and life.CBCT equipment has been commercialized in both hardwar...Cone-beam computed tomography(CBCT),a modern technique with many applications,is becoming increasingly important and essential in many areas of economics and life.CBCT equipment has been commercialized in both hardware and software.However,having a device system suitable for a specific group of objects will be the best.This work used Monte Carlo simulation to optimize the design of a Cone-beam Computed Tomography(CBCT)for lightweight and small-size casts.Factors affecting image quality such as radiation-source,flat-panel detector,and geometrical distance were investigated.Simulation results indicate that an X-ray generator with a focal spot size of 4×4µm^(2),high voltage of 240 kV,and a radiation intensity of 10^(13) photon/s with a flat panel CsI(Tl)detector of 0.3 mm thickness and a pixel size of 0.1–0.2 mm,is suitable for a CBCT to inspect small objects in industry.The Monte Carlo model was validated against experiments and to evaluate some characteristics of the existing system.展开更多
Electroslag remelting(ESR) is an important metallurgical process for producing high-purity materials with homogeneous compositions and sound microstructures,and its typical products are ingots or simple castings.The c...Electroslag remelting(ESR) is an important metallurgical process for producing high-purity materials with homogeneous compositions and sound microstructures,and its typical products are ingots or simple castings.The core principle involves the resistive melting of a consumable electrode within a slag pool,followed by the refining of molten metal droplets as they traverse the slag,and subsequent sequential solidification in a water-cooled mold.However,conventional ESR processes face limitations in producing large or complex-shaped components,enhancing production efficiency,achieving highly specialized microstructures,and meeting ultra-high purity demands for advanced applications.Advanced composite ESR technologies have been developed to overcome these limitations by innovatively modifying key process aspects.For instance,electrode systems are improved using vibration,rotation,or multiple electrodes.Enhanced mold design and solidification control are achieved through techniques including conductive molds,mold rotation,and ingot withdrawal.Precise control of the process is realized through the use of protective gas,vacuum,or elevated pressure,as well as the application of external fields such as magnetic fields or ultrasonic vibration.This review comprehensively summarizes these advanced techniques,examining their principles and characteristics,and discussing their specific advantages and challenges.展开更多
A parametric study was performed to explore the effect of runner thickness,filtration,and hydrogen content on the mechanical properties and defect formation in Al-7%Si-0.3%Mg(2L99)sand castings.A two-level full factor...A parametric study was performed to explore the effect of runner thickness,filtration,and hydrogen content on the mechanical properties and defect formation in Al-7%Si-0.3%Mg(2L99)sand castings.A two-level full factorial design of experiments was used to statistically evaluate these parameters and the tensile properties were characterized via Weibull distribution analysis.The findings reveal that decreasing the runner thickness from25 mm to 10 mm and using 10 PPI ceramic filters improve mechanical properties by minimizing double oxide film entrainment as confirmed by electron microscopy examination.In addition,lowering hydrogen concentrations within the Al alloy from 0.24 cm^(3)/100 g Al to 0.12 cm^(3)/100 g Al is also shown to enhance casting integrity by suppressing bifilm inflation and subsequent pore formation.ANOVA results indicate that the hydrogen content is the most important factor,contributing 53%to the variability in mechanical properties,followed by filtration(25%)and runner thickness(17%).The optimized casting conditions including thin runners(10 mm thick),melt filtration,and a low hydrogen level(0.12 cm^(3)/100 g Al),result in an approximately 474%increase in the shape factor and a 107%increase in the characteristic life of UTS,as well as an approximately 413%increase in the shape factor and a 149%increase in characteristic life of elongation.The outcomes suggest that controlled filling systems and melt treatment are critical for producing consistent,high integrity aluminum castings in industrial applications.展开更多
To develop a suitable production process for fiber reinforced investment casting shell mold,three methods were studied:the traditional method(M_(1)),the method of adding fiber into silica sol with mechanical stirring ...To develop a suitable production process for fiber reinforced investment casting shell mold,three methods were studied:the traditional method(M_(1)),the method of adding fiber into silica sol with mechanical stirring and ultrasonic agitation(M_(2)),and the method of adding fiber into slurry with mechanical stirring and ultrasonic agitation for durations of 3,15,30,and 45 min(M_(3)).The bending strength,high-temperature self-load deformation,and thermal conductivity of the shell molds were investigated.The results reveal that the enhancement of fiber dispersion through ultrasonic agitation improves the comprehensive performance of the shell molds.The maximum green bending strength of the shell mold by M_(2) reaches 3.29 MPa,which is 29% higher than that of the shell mold prepared by M_(1).Moreover,the high-temperature self-load deformation of the shell mold is reduced from 0.62% to 0.44%.In addition,simultaneous ultrasonic agitation and mechanical stirring effectively shorten the slurry preparation time while maintaining comparable levels of fiber dispersion.With the process M_(3)-45 min,the fillers are uniformly dispersed in the slurry,and the fired bending strength and the high-temperature self-load deformation reach 6.25 MPa and 0.41%,respectively.Therefore,the proposed ultrasonic agitation route is promising for the fabrication of fiber-reinforced shell molds with excellent fibers dispersion.展开更多
Centrifugal casting of ductile iron pipe is a high-temperature,semi-continuous production process.However,conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presen...Centrifugal casting of ductile iron pipe is a high-temperature,semi-continuous production process.However,conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presents significant challenges.In this study,a novel research method was introduced for investigating the solidification process of ductile iron pipe,namely thermal simulation of ductile iron pipe.Comparative research was conducted on the microstructure and properties of the thermal simulation sample and the ductile iron pipe.The findings indicate that the thermal simulation sample and ductile iron pipe exhibit good heat transfer similarity and microstructure similarity.The difference of cooling rate between thermal simulation sample and ductile pipe is less than 0.24℃·s^(-1),and the difference of microstructure content of free cementite,ferrite,and pearlite is less than 5%.The tensile strength of annealed ductile iron pipe is 466 MPa,with an elongation of 16.1%and a Brinell hardness of 156.5 HBW.In comparison,the tensile strength of annealed thermal simulation sample is 482.0 MPa,with an elongation of 15.5%and a Brinell hardness of 159.0 HBW.These results suggest that the thermal simulation experimental research method is both scientific and feasible,offering an objective,reliable,and cost-effective approach to laboratory research on ductile iron pipe.展开更多
The refinement of the as-cast grain structure in austenitic heat-resistant stainless steel depends on the formation of active solid nuclei during solidification.Titanium(Ti)additions successfully induced the formation...The refinement of the as-cast grain structure in austenitic heat-resistant stainless steel depends on the formation of active solid nuclei during solidification.Titanium(Ti)additions successfully induced the formation of Ti-containing inclusions,enhancing heterogeneous nucleation and promoting equiaxed dendritic growth in 347H stainless steel.Thermal simulation experiments indicated that the equiaxed crystal ratios increased notably with Ti content;samples with 0.06,0.12,and 0.36 wt.%Ti exhibited equiaxed ratios of 18%,24%,and 41%,respectively.Three primary inclusion types—TiN,Al_(2)O_(3)-TiN,and TiO_(x)-TiN—were identified at the cores of equiaxed dendrites,with nucleation core sizes predominantly ranging from 0.5 to 8μm.Among the tested samples,the 0.36 wt.%Ti addition produced the highest nucleation core density.Increasing Ti content significantly elevated dendrite tip undercooling from 2.6 K(0.06 wt.%Ti)to 10.8 K(0.36 wt.%Ti),accelerating solidification front instability and thus enhancing heterogeneous nucleation.Additionally,higher Ti content increased the divergence angle between adjacent columnar dendrites,further promoting the columnar-to-equiaxed transition(CET).展开更多
The Cu-12Fe alloy has attracted significant attention due to its excellent electrical conductivity and electromagnetic shielding capability,high strength,cost-effectiveness,and recyclability.In the present work,the Cu...The Cu-12Fe alloy has attracted significant attention due to its excellent electrical conductivity and electromagnetic shielding capability,high strength,cost-effectiveness,and recyclability.In the present work,the Cu-12Fe alloy strip with the thickness of 2.4 mm was successfully produced by twin-roll strip casting.The microstructure and properties of the Cu-12Fe alloy were tailored by cold rolling and aging treatment.The tensile strength of the as-cast strip is approximately 328 MPa and its elongation is 25%.The Fe phase randomly dispersed in the matrix,and the average size of Fe-rich phase is 2μm.Besides,enrichment of Fe phase is observed in the central layer of the strip,results in the formation of the“sandwich structure”.Moreover,the as-cast strip of Cu-12Fe was directly cold-rolled from 2.4 to 0.12 mm.The directly cold-rolled sample after aging at 450℃for 16 h(ProcessⅠ)shows excellent electrical conductivity of 69.5%IACS,the tensile strength and elongation are 513 MPa and 3.8%,the saturation magnetic flux density is 20.1 emu·g^(-1),and the coercive force is 25.2 Oe.In ProcessⅡ,the as-cast strip firstly cold-rolled to 1.2 mm,then aged at 500℃for 1.5 h,followed by cold rolling to 0.12 mm,finally aged at 450℃for 16 h.The sample after ProcessⅡshows the electrical conductivity of 66.3%IACS,the tensile strength of 533 MPa,an elongation of 3.5%,saturation magnetic flux density of 21.4 emu·g^(-1),and the coercive force of 22.3 Oe.展开更多
The transient phenomena of re-oxidation and slag entrapment occurring in the tundish during the ladle change-over process have been proven detrimental to clean steel production.Therefore,an unsteady three-phase turbul...The transient phenomena of re-oxidation and slag entrapment occurring in the tundish during the ladle change-over process have been proven detrimental to clean steel production.Therefore,an unsteady three-phase turbulence model,coupling velocity,temperature,and phase field was established to study the effect of the ladle shroud immersion depth on the slag eye formation,slag entrainment,slag dragging,air dragging,and flow characteristics during the ladle change-over process of a two-strand tundish.The results showed that reducing the immersion depth decreases the high-velocity region area under the slag layer in the quasi-steady process.During the emptying stage,as the molten bath level gradually decreases,the outlet temperature exhibits a trend of initially decreasing and subsequently increasing across all three shroud immersion depths.However,under a 210 mm shroud immersion depth,molten slag and air are dragged into the shroud,forming slag droplets and causing significant fluctuations,with a maximum scalar velocity of 0.0764 m/s at the monitoring point.In the filling stage,air and molten slag are dragged into the molten bath,forming bubbles and slag droplets at an immersion depth of 210 mm.Bubbles are observed within the molten slag layer,which can readily cause an emulsification phenomenon,making it easier to be dragged as slag droplets.Additionally,the slag eye area measured under 210 mm immersion depth at 45 s is 0.303 m^(2),while the maximum scalar velocity of 2.4259 m/s is detected at 12 s.At an immersion depth of 360 mm,the average area of the slag eye is minimized to 0.06268 m2,with corresponding variances of 0.006753,representing the optimal immersion depth.展开更多
A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel.The cross-sectional microstructural analysi...A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel.The cross-sectional microstructural analysis of typical slag rims for two highly crystalline powders revealed that their formation was primarily driven by the solidification of the liquid slag.Distinct differences were observed in the microstructures of slag rims from the two powders.Powder A(characterized by a higher breaking temperature and viscosity)displayed alternating lamellar microstructures of coarse and fine phases,with the coarse phases composed of akermanite-gehlenite transition phases.In contrast,powder B(with a lower breaking temperature and viscosity)predominantly comprised regular akermanite-gehlenite crystals interspersed with a certain amount of glassy phases.Numerical simulations of a three-phase fluid flow coupled with heat transfer indicate that slag rim formation correlates with mold oscillation.Solidification of the liquid slag at the slag rim front predominantly occurs during the negative stroke of the mold oscillation.The average heating rate during the ascending stage of the mold reaches approximately 100 K·s^(−1),whereas the average cooling rate during the descending stage attains 400 K·s^(−1).This temperature variation leads to the formation of lamellar microstructures,whereas the ascending stage promotes the formation of coarse structures and thicker slag rims.Based on the powder properties,two distinct formation pathways exist for highly crystalline mold powders.For the powders with a higher breaking temperature,higher viscosity,and narrower solidification range(powder A),coarse microstructures and thicker slag rims were preferentially formed.For powders with lower breaking temperature and viscosity and wider solidification ranges(powder B),the liquid slag resisted rapid solidification,and the extended mushy zone allowed the partial liquid slag to persist at the slag rim front,promoting the formation of a thin slag rim.This study enhances the understanding of slag rim formation in highly crystalline mold powders and provides critical insights into the control of longitudinal surface cracks in hypo-peritectic steel.展开更多
Cast aluminum(Al)alloys,owing to their low density and high specific strength,offer significant advantages in the fabrication of complex,large-scale,or monolithic structural components across civilian,defense,and mili...Cast aluminum(Al)alloys,owing to their low density and high specific strength,offer significant advantages in the fabrication of complex,large-scale,or monolithic structural components across civilian,defense,and military sectors that are weight-sensitive,including transportation,aerospace,and underwater weaponry.However,a substantial portion of these alloys often exhibit pronounced hot tearing susceptibility(HTS)during casting,which not only detrimentally affects the quality and efficiency of industrial production but also limits their further development in high-tech applications.Therefore,a comprehensive and profound understanding of hot tearing behavior in cast Al alloys is essential.This review first analyzes the formation mechanisms of hot tearing,encompassing strength theory,liquid film theory,intergranular bridging theory,solidification shrinkage compensation theory,and relevant models,as well as the key factors governing its occurrence,including alloy composition,grain structure,casting parameters,and inclusions.It then introduces current research methods,ranging from simple evaluation and physical parameter-based approaches to in situ observation and numerical simulation,followed by a summary of newly proposed hot tearing criteria.Finally,it discusses the remaining scientific challenges and outlines future research directions.Particular emphasis is placed on recent advances in the hot tearing of cast Al alloys over the past decade.展开更多
Al-Si-Cu-Mg alloy demonstrates a significant age-hardening effect,with its mechanical properties tunable by optimizing the aging parameters.To enhance this effect,the as-cast Al-8.5Si-2Cu-0.9Mg alloy was subjected to ...Al-Si-Cu-Mg alloy demonstrates a significant age-hardening effect,with its mechanical properties tunable by optimizing the aging parameters.To enhance this effect,the as-cast Al-8.5Si-2Cu-0.9Mg alloy was subjected to either single-stage aging at temperatures of 150℃,175℃,200℃,and 225℃for 0.5 h to 20 h;or double-stage aging:involving a first-stage aging treatment at 120℃for 1 h,3 h,5 h,or 7 h,followed by a second-stage aging treatment at 175℃ for 0.5 h to 20 h.The microstructure and mechanical properties were evaluated for samples aged at 175℃/7 h,175℃/10 h,120℃/5 h+175℃/5 h,and 120℃/5 h+175℃/8 h.XRD analysis reveals that the as-cast Al-8.5Si-2Cu-0.9Mg alloy consists of theα-Al,Si,θ-Al_(2)Cu,and Q-Al_(5)Cu_(2)Mg_8Si_6phases.The aging kinetics exhibit a double-peak behavior in both single-stage and double-stage aging processes.Under single-stage aging at 175℃/x h and double-stage aging(120℃/5 h+175℃/x h),the precipitates'size at the first peak is smaller than that at the second peak.Compared with single-stage aging(175℃/7 h),double-stage aging(120℃/5 h+175℃/5 h)produces a finer precipitate in the alloy.Theoretical calculations indicate that the number density and nucleation rate of both the Al_(5)Cu_(2)Mg_8Si_6 and Al_(2)Cu phases are higher during the double-stage aging(120℃/5 h+175℃/5 h)than those during the single-stage aging(175℃/7 h).Additionally,tensile tests at both room temperature and 250℃demonstrate that double-stage aging(120℃/5 h+175℃/5 h)significantly improves the mechanical properties of the alloy compared to single-stage aging(175℃/7 h),suggesting that double-stage aging is more effective for enhancing mechanical properties for this alloy.展开更多
The esophagus is a tubular organ essential for maintaining normal eating function in humans.However,the replacement of the esophagus remains challenging in clinical settings.Although tissue engineering scaffolds are a...The esophagus is a tubular organ essential for maintaining normal eating function in humans.However,the replacement of the esophagus remains challenging in clinical settings.Although tissue engineering scaffolds are a promising alternative solution,their fabrication is difficult due to the complex structure and function of the esophagus.This review describes the existing fabrication methods for esophageal tubular scaffolds,including decellularization,casting,electrospinning,three dimensional(3 D)bioprinting,and pin-frogging.Also discussed are the stimulation cues of the fabricated esophageal tubular scaffold that induce esophageal muscle and epithelial cells.Finally,this review emphasizes three important concerns for esophageal tubular scaffolds:leakage and porosity,elasticity and proliferation of smooth muscle cells,and biocompatibility and structural fidelity of biomaterials.展开更多
文摘The International STEM Education Forum in Suzhouopened in Soochow University on May 30, attractingscholars and experts in STEM education and cultivatingtechnology talents from home and abroad.Under the guidance of Department of Foreign ExpertsServices, Ministry of Science and Technology(MOST ), the event was jointly organized by ForeignTalent Research Center,Ministry of Science and Technologyand China Guanghua Foundation.
文摘AIM:To investigate the pathogenesis of biliary casts after liver transplantation relative to their morphology and biochemical markers.METHODS:The microstructure of biliary casts was assessed using scanning electron microscopy and Hematoxylin and eosin staining assessed their histology.The expression levels of CD3,CD5,CD34,CD68 and CD79a in these biliary casts were evaluated immunohistochemically.RESULTS:Biliary casts differed widely in their microstructure,with some containing blood vessels positive for CD34 and collagen fibers with positive Masson staining.Large numbers of neutrophils and other inflammatory cells were present,but only on the edge of the biliary casts;although the boundaries were clear without crossover.None of the biliary casts contained T-lymphocytes,B-lymphocytes,macrophages and other inflammatory cells.CONCLUSION:The microcostructure of biliary casts differed.Bacteria and acute rejection are not clearly related to their formation.
文摘Objective: This study presents the microvasculature of the horse iris, ciliary process, retina, and choroid and discusses the functional significance of the vasculature. Procedure: Seven horses were used for this study. The ocular vascular system was injected with methylmethacrylate resin via the carotid artery, and the vascular corrosion casts were observed using a scanning electron microscope. Results: The iridial vessels showed a wavy course. The ciliary process was supplied by 2 arterial routes: the iridial and ciliary arterial circles. The subjects displayed a paurangiotic retina with retinal vessels extending only a short distance around the disc. The retinal arterioles and venules ran in closely related pairs, and the capillaries formed hairpin loops. No central retinal artery was seen in the equine eyes examined. The choriocapillaris in the avascular retina was arranged in honeycomb hexagon lobules and formed a more densely packed network than that in the vascular retina. There were 2 distinct venous drainage systems in the horse choroid: the vortex veins and the posterior ciliary veins. The vortex vein ampulla was flattened and showed a slit-like lumen at the merge site with the ophthalmic vein. The vortex veins demonstrated a marked constriction before leaving the eye. Discussion: The 2 choroidal drainage systems may compensate each other in event of occlusion. The ampulla and the constriction in the vortex veins may act as a valve regulating the blood flow to keep the eye at an optimum size and the intraocular pressure within the normal physiological range.
基金We thank the Agriculture,Fisheries and Conservation Department of the Hong Kong SAR Government(China)for the permission of field sampling.
文摘Effects of earthworm casts on soil nutrient dynamics and their responses to changing moisture availability in subtropical ecosystems remain poorly understood.This study aimed to examine short-term carbon(C)and nitrogen(N)dynamics and their interactions with wetting-drying cycles in three different structural forms(i.e.,granular,globular,and heap-like)of Amynthas earthworm casts.The rates of C and N mineralization in the earthworm casts were examined under two different wetting-drying cycles(i.e.,2-d and 4-d wetting intervals)using a rainfall simulation experiment.After three simulated rainfall events,subsamples of the earthworm casts were further incubated for 4 d for the determination of CO2 and N2O fluxes.The results of this study indicated that the impacts of wetting-drying cycles on the short-term C and N dynamics were highly variable among the three cast forms,but wetting-drying cycles significantly reduced the cumulative CO2 and N2O fluxes by 62%-83%and 57%-85%,respectively,when compared to the control without being subjected to any rainfall events.The C mineralization rates in different cast forms were affected by the amount of organic substrates and N content in casts,which were associated with the food preference and selection of earthworms.Meanwhile,the cumulative N2O fluxes did not differ among the three cast forms.Repeated wetting and drying of casts not only enhanced aggregate stability by promoting bonds between the cast particles,but also inhibited microbial survival and growth during the prolonged drying period,which together hindered decomposition and denitrification.Our findings demonstrated that the interactions between the structural forms,aggregate dynamics,and C and N cycling in the earthworm casts were highly complex.
文摘AIM To determine if complete, split casts and backslabs [plaster of Paris(POP) and fiberglass] generate different intracast pressures and pain. METHODS Increased swelling within casts was modeled by a closed water system attached to an expandable bag placed directly under different types of casts applied to a healthy lower limb. Complete fiberglass and POP casts, split casts and backslabs were applied. Twenty-five milliliter aliquots of saline were injected into the system and the generated intracast pressures were measured using a sphygmomanometer. The subject was blinded to the pressure scores to avoid bias. All casts were applied to the same right limb on the same subject to avoid the effects of variations in anatomy or physiology on intracast pressures. Pain levels were evaluated using the Visual Analogue Score after each sequential saline injection. Each type of cast was reapplied four times and the measurements were repeated on four separate occasions. Sample sizes were determined by a pre-study 90% power calculation to detect a 20% difference in intracast pressures between cast groups. RESULTS A significant difference between the various types of casts was noted when the saline volume was greater than 100 mL(P = 0.009). The greatest intracast pressure was generated by complete fiberglass casts, which were significantly higher than complete POP casts or backslabs(P = 0.018 and P = 0.008 respectively) at intracast saline volumes of 100 mL and higher. Backslabs produced a significantly lower intracast pressure compared to complete POP only once the saline volume within casts exceeded 225 mL(P = 0.009). Intracast pressures were significantly lower in split casts(P = 0.003). Split POP and fiberglass casts produced the lowest intracast pressures, even compared to backslabs(P = 0.009). Complete fiberglass casts generated the highest pain levels at manometer pressures of 75 mm Hg and greater(P = 0.001). Split fiberglass casts had significantly reduced pain levels(P = 0.001). In contrast, a split complete POP cast did not produce significantly reduced pain levels at pressures between 25-150 mmH g. There was no difference in pain generated by complete POP and backslabs at manometer pressures of 200 mm Hg and lower. CONCLUSION Fibreglass casts generate significantly higher intracast pressures and pain than POP casts. Split casts cause lower intracast pressures regardless of material, than complete casts and backslabs.
文摘The internal cracks in continuously cast slabs are attributed to the excessive tensile strain occurring at the solidifying frontduring the continuous casting process. Based on the understanding, a model for diagnosing the formation of the internal cracks was established, in which the strains at the solidifying front caused by' bulging, straightening or unbending, and roll misalignment were calculated and compared with a critical strain value to estimate whether the internal cracks form. Moreover, the established model was appliedto a real slab caster to reveal the distribution of the strains in casting direction and its effect on the internal cracks. It was proved that themodel was reliable and useful for optimizing the operation of continuous casting.
文摘Purpose:Secondary displacement represents a frequent complication of conservative treatment of fractures,particularly of the distal radius.The gap space between skin and cast may lead to a certain degree movements and this increased mobility might favor redisplacement.The aim of this study was to develop a new 3D method,to measure the gap space in all 3 geometrical planes,and to validate this new technique in a clinical setting of distal radius fractures.Methods:This study applies 3D imaging to measure the space between plaster and skin as a potential factor of secondary displacement and therefore the failure of conservative treatment.We developed and validated a new methodology to analyze and compare different forearm casts made of plaster of Paris and fiberglass.An unpaired t-test was performed to document differences between the investigated parameters between plaster of Paris and fiberglass casts.The significance level was set at p<0.05.Results:In a series of 15 cases,we found the width of the gap space to average 4 mm,being slightly inferior on the radial side.Comparing the two different casting materials,plaster of Paris and fiberglass,we found a significantly larger variance of space under casts made of the first material(p=0.39).A roughness analysis showed also a markedly significantly higher irregularity of the undersurface of plaster of Paris as compared with fiberglass.Conclusion:This study allows for a better understanding of the nature of the"gap space"between cast and skin and will contribute to develop and improve new immobilization techniques and materials.
基金The work presented in this paper has been funded by the Vietnamese Ministry of Science&Technology,Contract Number KC.05.18/16-20.
文摘Cone-beam computed tomography(CBCT),a modern technique with many applications,is becoming increasingly important and essential in many areas of economics and life.CBCT equipment has been commercialized in both hardware and software.However,having a device system suitable for a specific group of objects will be the best.This work used Monte Carlo simulation to optimize the design of a Cone-beam Computed Tomography(CBCT)for lightweight and small-size casts.Factors affecting image quality such as radiation-source,flat-panel detector,and geometrical distance were investigated.Simulation results indicate that an X-ray generator with a focal spot size of 4×4µm^(2),high voltage of 240 kV,and a radiation intensity of 10^(13) photon/s with a flat panel CsI(Tl)detector of 0.3 mm thickness and a pixel size of 0.1–0.2 mm,is suitable for a CBCT to inspect small objects in industry.The Monte Carlo model was validated against experiments and to evaluate some characteristics of the existing system.
基金supported by the National Natural Science Foundation of China (NSFC 52175352)。
文摘Electroslag remelting(ESR) is an important metallurgical process for producing high-purity materials with homogeneous compositions and sound microstructures,and its typical products are ingots or simple castings.The core principle involves the resistive melting of a consumable electrode within a slag pool,followed by the refining of molten metal droplets as they traverse the slag,and subsequent sequential solidification in a water-cooled mold.However,conventional ESR processes face limitations in producing large or complex-shaped components,enhancing production efficiency,achieving highly specialized microstructures,and meeting ultra-high purity demands for advanced applications.Advanced composite ESR technologies have been developed to overcome these limitations by innovatively modifying key process aspects.For instance,electrode systems are improved using vibration,rotation,or multiple electrodes.Enhanced mold design and solidification control are achieved through techniques including conductive molds,mold rotation,and ingot withdrawal.Precise control of the process is realized through the use of protective gas,vacuum,or elevated pressure,as well as the application of external fields such as magnetic fields or ultrasonic vibration.This review comprehensively summarizes these advanced techniques,examining their principles and characteristics,and discussing their specific advantages and challenges.
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(Grant number IMSIU-DDRSP2603)。
文摘A parametric study was performed to explore the effect of runner thickness,filtration,and hydrogen content on the mechanical properties and defect formation in Al-7%Si-0.3%Mg(2L99)sand castings.A two-level full factorial design of experiments was used to statistically evaluate these parameters and the tensile properties were characterized via Weibull distribution analysis.The findings reveal that decreasing the runner thickness from25 mm to 10 mm and using 10 PPI ceramic filters improve mechanical properties by minimizing double oxide film entrainment as confirmed by electron microscopy examination.In addition,lowering hydrogen concentrations within the Al alloy from 0.24 cm^(3)/100 g Al to 0.12 cm^(3)/100 g Al is also shown to enhance casting integrity by suppressing bifilm inflation and subsequent pore formation.ANOVA results indicate that the hydrogen content is the most important factor,contributing 53%to the variability in mechanical properties,followed by filtration(25%)and runner thickness(17%).The optimized casting conditions including thin runners(10 mm thick),melt filtration,and a low hydrogen level(0.12 cm^(3)/100 g Al),result in an approximately 474%increase in the shape factor and a 107%increase in the characteristic life of UTS,as well as an approximately 413%increase in the shape factor and a 149%increase in characteristic life of elongation.The outcomes suggest that controlled filling systems and melt treatment are critical for producing consistent,high integrity aluminum castings in industrial applications.
基金supported by the National Natural Science Foundation of China (Grant No. 5186504)the University Science Foundation for Young Science and Technology Talents in Inner Mongolia Autonomous Region of China (Grant No. NJYT22078)+2 种基金the Basic Scientific Research Expenses Program of Universities directly under Inner Mongolia Autonomous Region (Grant No. JY20220059)the Inner Mongolia Autonomous Region ‘Grassland Talent’ project Young Innovative Talent Training Program Level ⅠBasic Research Expenses of Universities directly under the Inner Mongolia Autonomous Region (Grant No. ZTY2023040)。
文摘To develop a suitable production process for fiber reinforced investment casting shell mold,three methods were studied:the traditional method(M_(1)),the method of adding fiber into silica sol with mechanical stirring and ultrasonic agitation(M_(2)),and the method of adding fiber into slurry with mechanical stirring and ultrasonic agitation for durations of 3,15,30,and 45 min(M_(3)).The bending strength,high-temperature self-load deformation,and thermal conductivity of the shell molds were investigated.The results reveal that the enhancement of fiber dispersion through ultrasonic agitation improves the comprehensive performance of the shell molds.The maximum green bending strength of the shell mold by M_(2) reaches 3.29 MPa,which is 29% higher than that of the shell mold prepared by M_(1).Moreover,the high-temperature self-load deformation of the shell mold is reduced from 0.62% to 0.44%.In addition,simultaneous ultrasonic agitation and mechanical stirring effectively shorten the slurry preparation time while maintaining comparable levels of fiber dispersion.With the process M_(3)-45 min,the fillers are uniformly dispersed in the slurry,and the fired bending strength and the high-temperature self-load deformation reach 6.25 MPa and 0.41%,respectively.Therefore,the proposed ultrasonic agitation route is promising for the fabrication of fiber-reinforced shell molds with excellent fibers dispersion.
基金financially supported by the National Natural Science Foundation of China(52130109)。
文摘Centrifugal casting of ductile iron pipe is a high-temperature,semi-continuous production process.However,conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presents significant challenges.In this study,a novel research method was introduced for investigating the solidification process of ductile iron pipe,namely thermal simulation of ductile iron pipe.Comparative research was conducted on the microstructure and properties of the thermal simulation sample and the ductile iron pipe.The findings indicate that the thermal simulation sample and ductile iron pipe exhibit good heat transfer similarity and microstructure similarity.The difference of cooling rate between thermal simulation sample and ductile pipe is less than 0.24℃·s^(-1),and the difference of microstructure content of free cementite,ferrite,and pearlite is less than 5%.The tensile strength of annealed ductile iron pipe is 466 MPa,with an elongation of 16.1%and a Brinell hardness of 156.5 HBW.In comparison,the tensile strength of annealed thermal simulation sample is 482.0 MPa,with an elongation of 15.5%and a Brinell hardness of 159.0 HBW.These results suggest that the thermal simulation experimental research method is both scientific and feasible,offering an objective,reliable,and cost-effective approach to laboratory research on ductile iron pipe.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3700602)the Jiaxing Key Research and Development Program(Grant No.2022BZ10010).
文摘The refinement of the as-cast grain structure in austenitic heat-resistant stainless steel depends on the formation of active solid nuclei during solidification.Titanium(Ti)additions successfully induced the formation of Ti-containing inclusions,enhancing heterogeneous nucleation and promoting equiaxed dendritic growth in 347H stainless steel.Thermal simulation experiments indicated that the equiaxed crystal ratios increased notably with Ti content;samples with 0.06,0.12,and 0.36 wt.%Ti exhibited equiaxed ratios of 18%,24%,and 41%,respectively.Three primary inclusion types—TiN,Al_(2)O_(3)-TiN,and TiO_(x)-TiN—were identified at the cores of equiaxed dendrites,with nucleation core sizes predominantly ranging from 0.5 to 8μm.Among the tested samples,the 0.36 wt.%Ti addition produced the highest nucleation core density.Increasing Ti content significantly elevated dendrite tip undercooling from 2.6 K(0.06 wt.%Ti)to 10.8 K(0.36 wt.%Ti),accelerating solidification front instability and thus enhancing heterogeneous nucleation.Additionally,higher Ti content increased the divergence angle between adjacent columnar dendrites,further promoting the columnar-to-equiaxed transition(CET).
基金financially supported by the Natural Science Foundation of Liaoning Province of China(2022-MS-109)the Key Research and Development Program of Liaoning Province(2023JH2/101800045)the Ministry of Science and Technology of the Peoples Republic of China(ZZ2021006).
文摘The Cu-12Fe alloy has attracted significant attention due to its excellent electrical conductivity and electromagnetic shielding capability,high strength,cost-effectiveness,and recyclability.In the present work,the Cu-12Fe alloy strip with the thickness of 2.4 mm was successfully produced by twin-roll strip casting.The microstructure and properties of the Cu-12Fe alloy were tailored by cold rolling and aging treatment.The tensile strength of the as-cast strip is approximately 328 MPa and its elongation is 25%.The Fe phase randomly dispersed in the matrix,and the average size of Fe-rich phase is 2μm.Besides,enrichment of Fe phase is observed in the central layer of the strip,results in the formation of the“sandwich structure”.Moreover,the as-cast strip of Cu-12Fe was directly cold-rolled from 2.4 to 0.12 mm.The directly cold-rolled sample after aging at 450℃for 16 h(ProcessⅠ)shows excellent electrical conductivity of 69.5%IACS,the tensile strength and elongation are 513 MPa and 3.8%,the saturation magnetic flux density is 20.1 emu·g^(-1),and the coercive force is 25.2 Oe.In ProcessⅡ,the as-cast strip firstly cold-rolled to 1.2 mm,then aged at 500℃for 1.5 h,followed by cold rolling to 0.12 mm,finally aged at 450℃for 16 h.The sample after ProcessⅡshows the electrical conductivity of 66.3%IACS,the tensile strength of 533 MPa,an elongation of 3.5%,saturation magnetic flux density of 21.4 emu·g^(-1),and the coercive force of 22.3 Oe.
基金supported by the National Natural Science Foundation of China(Nos.52422408 and 52171031)the Liaoning Xingliao Talents-Top-notch Young Talents Project(No.XLYC2203064)+1 种基金the Excellent Youth Fund of Liaoning Natural Science Foundation(No.2023JH3/10200001)the Fundamental Research Funds for the Central Universities(No.N2425004).
文摘The transient phenomena of re-oxidation and slag entrapment occurring in the tundish during the ladle change-over process have been proven detrimental to clean steel production.Therefore,an unsteady three-phase turbulence model,coupling velocity,temperature,and phase field was established to study the effect of the ladle shroud immersion depth on the slag eye formation,slag entrainment,slag dragging,air dragging,and flow characteristics during the ladle change-over process of a two-strand tundish.The results showed that reducing the immersion depth decreases the high-velocity region area under the slag layer in the quasi-steady process.During the emptying stage,as the molten bath level gradually decreases,the outlet temperature exhibits a trend of initially decreasing and subsequently increasing across all three shroud immersion depths.However,under a 210 mm shroud immersion depth,molten slag and air are dragged into the shroud,forming slag droplets and causing significant fluctuations,with a maximum scalar velocity of 0.0764 m/s at the monitoring point.In the filling stage,air and molten slag are dragged into the molten bath,forming bubbles and slag droplets at an immersion depth of 210 mm.Bubbles are observed within the molten slag layer,which can readily cause an emulsification phenomenon,making it easier to be dragged as slag droplets.Additionally,the slag eye area measured under 210 mm immersion depth at 45 s is 0.303 m^(2),while the maximum scalar velocity of 2.4259 m/s is detected at 12 s.At an immersion depth of 360 mm,the average area of the slag eye is minimized to 0.06268 m2,with corresponding variances of 0.006753,representing the optimal immersion depth.
基金supported by the National Natural Science Foundation of China(No.52274318).
文摘A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel.The cross-sectional microstructural analysis of typical slag rims for two highly crystalline powders revealed that their formation was primarily driven by the solidification of the liquid slag.Distinct differences were observed in the microstructures of slag rims from the two powders.Powder A(characterized by a higher breaking temperature and viscosity)displayed alternating lamellar microstructures of coarse and fine phases,with the coarse phases composed of akermanite-gehlenite transition phases.In contrast,powder B(with a lower breaking temperature and viscosity)predominantly comprised regular akermanite-gehlenite crystals interspersed with a certain amount of glassy phases.Numerical simulations of a three-phase fluid flow coupled with heat transfer indicate that slag rim formation correlates with mold oscillation.Solidification of the liquid slag at the slag rim front predominantly occurs during the negative stroke of the mold oscillation.The average heating rate during the ascending stage of the mold reaches approximately 100 K·s^(−1),whereas the average cooling rate during the descending stage attains 400 K·s^(−1).This temperature variation leads to the formation of lamellar microstructures,whereas the ascending stage promotes the formation of coarse structures and thicker slag rims.Based on the powder properties,two distinct formation pathways exist for highly crystalline mold powders.For the powders with a higher breaking temperature,higher viscosity,and narrower solidification range(powder A),coarse microstructures and thicker slag rims were preferentially formed.For powders with lower breaking temperature and viscosity and wider solidification ranges(powder B),the liquid slag resisted rapid solidification,and the extended mushy zone allowed the partial liquid slag to persist at the slag rim front,promoting the formation of a thin slag rim.This study enhances the understanding of slag rim formation in highly crystalline mold powders and provides critical insights into the control of longitudinal surface cracks in hypo-peritectic steel.
基金financially supported by the National Natural Science Foundation of China(No.52475380)the inaugural Young Elite Scientists Sponsorship Program(Doctoral Student Special Plan)of the China Association for Science and Technology(CAST)。
文摘Cast aluminum(Al)alloys,owing to their low density and high specific strength,offer significant advantages in the fabrication of complex,large-scale,or monolithic structural components across civilian,defense,and military sectors that are weight-sensitive,including transportation,aerospace,and underwater weaponry.However,a substantial portion of these alloys often exhibit pronounced hot tearing susceptibility(HTS)during casting,which not only detrimentally affects the quality and efficiency of industrial production but also limits their further development in high-tech applications.Therefore,a comprehensive and profound understanding of hot tearing behavior in cast Al alloys is essential.This review first analyzes the formation mechanisms of hot tearing,encompassing strength theory,liquid film theory,intergranular bridging theory,solidification shrinkage compensation theory,and relevant models,as well as the key factors governing its occurrence,including alloy composition,grain structure,casting parameters,and inclusions.It then introduces current research methods,ranging from simple evaluation and physical parameter-based approaches to in situ observation and numerical simulation,followed by a summary of newly proposed hot tearing criteria.Finally,it discusses the remaining scientific challenges and outlines future research directions.Particular emphasis is placed on recent advances in the hot tearing of cast Al alloys over the past decade.
基金supported by the Key R&D Projects in Heilongjiang Province(GA23A901)。
文摘Al-Si-Cu-Mg alloy demonstrates a significant age-hardening effect,with its mechanical properties tunable by optimizing the aging parameters.To enhance this effect,the as-cast Al-8.5Si-2Cu-0.9Mg alloy was subjected to either single-stage aging at temperatures of 150℃,175℃,200℃,and 225℃for 0.5 h to 20 h;or double-stage aging:involving a first-stage aging treatment at 120℃for 1 h,3 h,5 h,or 7 h,followed by a second-stage aging treatment at 175℃ for 0.5 h to 20 h.The microstructure and mechanical properties were evaluated for samples aged at 175℃/7 h,175℃/10 h,120℃/5 h+175℃/5 h,and 120℃/5 h+175℃/8 h.XRD analysis reveals that the as-cast Al-8.5Si-2Cu-0.9Mg alloy consists of theα-Al,Si,θ-Al_(2)Cu,and Q-Al_(5)Cu_(2)Mg_8Si_6phases.The aging kinetics exhibit a double-peak behavior in both single-stage and double-stage aging processes.Under single-stage aging at 175℃/x h and double-stage aging(120℃/5 h+175℃/x h),the precipitates'size at the first peak is smaller than that at the second peak.Compared with single-stage aging(175℃/7 h),double-stage aging(120℃/5 h+175℃/5 h)produces a finer precipitate in the alloy.Theoretical calculations indicate that the number density and nucleation rate of both the Al_(5)Cu_(2)Mg_8Si_6 and Al_(2)Cu phases are higher during the double-stage aging(120℃/5 h+175℃/5 h)than those during the single-stage aging(175℃/7 h).Additionally,tensile tests at both room temperature and 250℃demonstrate that double-stage aging(120℃/5 h+175℃/5 h)significantly improves the mechanical properties of the alloy compared to single-stage aging(175℃/7 h),suggesting that double-stage aging is more effective for enhancing mechanical properties for this alloy.
基金support from the National Natural Science Foundation of China(No.82472440)Hubei Provincial Natural Science Foundation of China(No.2023AFB141)+1 种基金the National Medical Products Administration Key Laboratory for Dental Materials(No.PKUSS20240401)the Cross-Research Support Program from Huazhong University of Science and Technology。
文摘The esophagus is a tubular organ essential for maintaining normal eating function in humans.However,the replacement of the esophagus remains challenging in clinical settings.Although tissue engineering scaffolds are a promising alternative solution,their fabrication is difficult due to the complex structure and function of the esophagus.This review describes the existing fabrication methods for esophageal tubular scaffolds,including decellularization,casting,electrospinning,three dimensional(3 D)bioprinting,and pin-frogging.Also discussed are the stimulation cues of the fabricated esophageal tubular scaffold that induce esophageal muscle and epithelial cells.Finally,this review emphasizes three important concerns for esophageal tubular scaffolds:leakage and porosity,elasticity and proliferation of smooth muscle cells,and biocompatibility and structural fidelity of biomaterials.
