There is an urgent need to develop magnesium-matrix materials that exhibit both high thermal conductivity and low thermal expansion to ensure compatibility with chips.This study aims to develop a Mg-Zn-Cu alloy with h...There is an urgent need to develop magnesium-matrix materials that exhibit both high thermal conductivity and low thermal expansion to ensure compatibility with chips.This study aims to develop a Mg-Zn-Cu alloy with high thermal conductivity.Furthermore,it explores the preparation of AlN_(P)/Mg-Zn-Cu composites featuring low coefficients of thermal expansion.The stir casting method was utilized to fabricate the composites and an investigation was conducted to examine their microstructure and thermal properties.Results indicate that the addition of AlN_(P)reduces the thermal expansion coefficient while maintaining relatively high thermal conductivity.Specifically,the AlN_(P)/Mg-0.5Zn-0.5Cu composite with 30wt.%AlN_(P)achieves a thermal conductivity of 132.7 W·m^(-1)·K^(-1)and a thermal expansion coefficient of 18.5×10^(-6)K^(-1),rendering it suitable for electronic packaging applications where thermal management is critical.展开更多
Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the...Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the approach bridge.For long-span railway bridges,it must also be coordinated with rail expansion joint(REJ),which is necessary to accommodate the expansion and contraction of,and reducing longitudinal stress in,the rails.The main aim of this study is to present analysis of recent developments in the research and application of BEJs in high-speed railway(HSR)long-span bridges in China,and to propose a performance-based integral design method for BEJs used with REJs,from both theoretical and engineering perspectives.Design/methodology/approach–The study first presents a summary on the application and maintenance of BEJs in HSR long-span bridges in China representing an overview of their state of development.Results of a survey of typical BEJ faults were analyzed,and field testing was conducted on a railway cable-stayed bridge in order to obtain information on the major mechanical characteristics of its BEJ under train load.Based on the above,a performance-based integral design method for BEJs with maximum expansion range 1600 mm(±800 mm),was proposed,covering all stages from overall conceptual design to consideration of detailed structural design issues.The performance of the novel BEJ design thus derived was then verified via theoretical analysis under different scenarios,full-scale model testing,and field testing and commissioning.Findings–Two major types of BEJs,deck-type and through-type,are used in HSR long-span bridges in China.Typical BEJ faults were found to mainly include skewness of steel sleepers at the bridge gap,abnormally large longitudinal frictional resistance,and flexural deformation of the scissor mechanisms.These faults influence BEJ functioning,and thus adversely affect track quality and train running performance at the beam end.Due to their simple and integral structure,deck-type BEJs with expansion range 1200 mm(±600 mm)or less have been favored as a solution offering improved operational conditions,and have emerged as a standard design.However,when the expansion range exceeds the above-mentioned value,special design work becomes necessary.Therefore,based on engineering practice,a performance-based integral design method for BEJs used with REJs was proposed,taking into account four major categories of performance requirements,i.e.,mechanical characteristics,train running quality,durability and insulation performance.Overall BEJ design must mainly consider component strength and the overall stiffness of BEJ;the latter factor in particular has a decisive influence on train running performance at the beam end.Detailed BEJ structural design must stress minimization of the frictional resistance of its sliding surface.The static and dynamic performance of the newlydesigned BEJ with expansion range 1600 mm have been confirmed to be satisfactory,via numerical simulation,full-scale model testing,and field testing and commissioning.Originality/value–This research provides a broad overview of the status of BEJs with large expansion range in HSR long-span bridges in China,along with novel insights into their design.展开更多
Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the de...Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the degradation behavior and failure mechanism of various overcharged states(100%SOC,105%SOC,110%SOC,and 115%SOC),multiple advanced in-situ characterization techniques(accelerating rate calorimeter,electrochemical impedance spectroscopy,ultrasonic scanning,and expansion instrument)were utilized.Additionally,re-overcharge-induced thermal runaway(TR)tests were conducted,with a specific emphasis on the evolution of the expansion force signal.Results indicated significant degradation at 110%SOC including conductivity loss,loss of lithium inventory,and loss of active material accompanied by internal gas generation.These failure behaviors slow down the expansion force rate during reovercharging,reducing the efficacy of active warnings that depend on rate thresholds of expansion force.Specifically,the warning time for 115%SOC battery is only 144 s,which is 740 s shorter than that for fresh battery,and the time to TR is advanced by 9 min.Moreover,the initial self-heating temperature(T1)is reduced by 62.4℃compared to that of fresh battery,reaching only 70.8℃.To address the low safety of overcharged batteries,a passive overcharge warning method utilizing relaxation expansion force was proposed,based on the continued gas generation after stopping charging,leading to a sustained increase in force.Compared to active methods that rely on thresholds of expansion force rate,the passive method can issue warnings 115 s earlier.By combining the passive and active warning methods,guaranteed effective overcharge warning can be issued 863-884 s before TR.This study introduces a novel perspective for enhancing the safety of batteries.展开更多
Sulfate attack-induced expansion of cement-treated aggregates in seasonally frozen regions is a well-known issue which causes continuous expansion in railway subgrades,and particularly in high-speed railways.According...Sulfate attack-induced expansion of cement-treated aggregates in seasonally frozen regions is a well-known issue which causes continuous expansion in railway subgrades,and particularly in high-speed railways.Accordingly,we investigated the influence of material proportions,the number of freeze-thaw(FT)cycles,and temperature gradients on the expansion mechanism of sulfate attack on cement-treated aggregates subjected to FT cycles.The conditions,laws,and dominant factors causing the expansion of aggregates were analyzed through swelling tests.The results indicate that under FT cycles,3%content cement-treated graded macadam only experiences slight deformation.The maximum strain of graded macadam attacked by 1%sodium sulfate content in each FT cycle is significantly larger than that of 3%content cement-treated graded macadam attacked by 1%sodium sulfate content.Using scanning electron microscopy,needle-like crystals were observed during sulfate attack of cement-treated graded macadam.Through quantitative analysis,we determined the recoverable and unrecoverable deformations of graded macadam under FT cycles.For graded macadam under sulfate attack,the expansion is mainly induced by periodic frost heave and salt expansion,as well as salt migration.For cement-treated graded macadam under sulfate attack,the expansion is mainly induced by chemical attack and salt migration.This study can serve as a reference for future research on the mechanics of sulfate attack on cement-treated aggregates that experience FT cycles,and provide theoretical support for methods that remediate the expansion induced by sulfate attack.展开更多
Minimizing the thermal expansion coefficient(TEC)mismatch between the cathode and electrolyte in solid oxide fuel cells is crucial for achieving stable,durable operation and high performance.Recently,materials with ne...Minimizing the thermal expansion coefficient(TEC)mismatch between the cathode and electrolyte in solid oxide fuel cells is crucial for achieving stable,durable operation and high performance.Recently,materials with negative thermal expansion(NTE)have at-tracted significant attention as effective additives for tailoring the thermomechanical properties of electrodes and enhancing cell durability.In this work,for the first time,single-phase NTE perovskite Sm_(0.85)Zn_(0.15)MnO_(3−δ)(SZM15)was successfully synthesized via the sol-gel method,eliminating the unwanted ZnO phase typically observed in materials obtained through the conventional solid-state reaction route.The sol-gel approach proved highly advantageous,offering low cost,robustness,excellent chemical homogeneity,precise compositional control,and high phase purity.After optimization of synthesis parameters,a negative TEC of approximately−6.5×10^(−6)K^(−1)was achieved in the 400-850℃range.SZM15 was then incorporated as an additive(10wt%-50wt%)into a SmBa0.5Sr0.5CoCuO_(5+δ)(SBSCCO)cathode to tune the thermomechanical properties with a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ)(LSGM)electrolyte,achieving a minimal TEC mismatch of only 1%.Notably,the SBSCCO+10wt%SZM15 composite cathode exhibited the lowest polarization resistance of 0.019Ω·cm^(2)at 900℃,showing approximately 70%lower than that of the pristine cathode.Excellent long-term stability after 100 h of operation was achieved.In addition,a high peak power density of 680 mW·cm^(−2)was achieved in a Ni-YSZ(yttria-stabilized zirconia)|YSZ|Ce_(0.9)Gd_(0.1)O_(2−δ)(GDC10)|SBSCCO+10wt%SZM15 anode-supported fuel cell at 850℃,highlighting the effectiveness of incorporating NTE materials as a promising strategy for regulating the thermomechanical properties and improving the long-term stability of intermediate temperature solid oxide fuel cells(IT-SOFCs).展开更多
Negative thermal expansion(NTE)is a notable physical property where a material’s volume decreases instead of increasing when heated.The identification of NTE materials is crucial for thermal expansion control enginee...Negative thermal expansion(NTE)is a notable physical property where a material’s volume decreases instead of increasing when heated.The identification of NTE materials is crucial for thermal expansion control engineering.Most NTE materials exhibit NTE only within a narrow temperature range,restricting their applications.Achieving NTE across a broad temperature range remains a significant challenge.This study developed a novel PbTiO_(3)-based system,(1-x)PbTiO_(3–x)BiLuO_(3),incorporating rare-earth elements,using a distinctive high-pressure and high-temperature synthesis technique.We achieved NTE across a broad temperature range by coupling lattice(c/a)with ferroelectric order parameters.The incorporation of BiLuO_(3)resulted in distinctive ferroelectric characteristics,including increased tetragonality,spontaneous polarization,and NTE over a broad temperature range.NTE over an extended temperature range has been achieved in 0.95PbTiO_(3)–0.05BiLuO_(3)(■=−1.7×10^(–5)K^(−1),300–840 K)and 0.90PbTiO_(3)–0.10BiLuO_(3)(■=−1.4×10^(–5)K^(−1),300–860 K),compared to pristine PbTiO_(3)(■=−1.99×10^(–5)K^(−1),300–763 K).The improved tetragonalities and broader NTE temperature range result from the strong hybridization of Pb/Bi–O and Ti/Lu–O atoms,as demonstrated by combined experimental and theoretical analyses,including high-energy synchrotron X-ray diffraction,Raman spectroscopy,and density functional theory calculations.This study introduces a novel example of NTE over a broad temperature range,highlighting its potential as a high-performance thermal expansion compensator.Additionally,it presents an effective method for incorporating rare-earth elements to achieve NTE in PbTiO_(3)-based perovskites across a wide temperature range.展开更多
As a negative electrode material for lithium-ion batteries,silicon monoxide(SiO)suffers from dramatic volume changes during cycling,causing excessive stress within the electrode and resulting in electrode deformation ...As a negative electrode material for lithium-ion batteries,silicon monoxide(SiO)suffers from dramatic volume changes during cycling,causing excessive stress within the electrode and resulting in electrode deformation and fragmentation.This ultimately leads to a decrease in cell capacity.The trends of volume expansion and capacity change of the SiO/graphite(SiO/C)composite electrode during cycling were investigated via in situ expansion monitoring.First,a series of expansion test schemes were designed,and the linear relationship between negative electrode expansion and cell capacity degradation was quantitatively analyzed.Then,the effects of different initial pressures on the long-term cycling performance of the cell were evaluated.Finally,the mechanism of their effects was analyzed by scanning electron microscope.The results show that after 50 cycles,the cell capacity decreases from 2.556 mAh to 1.689 mAh,with a capacity retention ratio(CRR)of only 66.08%.A linear relationship between the capacity retention ratio and thickness expansion was found.Electrochemical measurements and scanning electron microscope images demonstrate that intense stress inhibits the lithiation of the negative electrode and that the electrode is more susceptible to irreversible damage during cycling.Overall,these results reveal the relationship between the cycling performance of SiO and the internal pressure of the electrode from a macroscopic point of view,which provides some reference for the application of SiO/C composite electrodes in lithium-ion batteries.展开更多
For the Sylvester continued fraction expansions of real numbers,FAN et al.(2007)proved that,for almost all real numbers,the nth partial quotient grows exponentially with respect to the product of the first n-1 partial...For the Sylvester continued fraction expansions of real numbers,FAN et al.(2007)proved that,for almost all real numbers,the nth partial quotient grows exponentially with respect to the product of the first n-1 partial quotients.In this paper,we establish the Hausdorff dimension of the exceptional set where the growth rate is a general function.展开更多
The effectiveness of cranial suture expansion therapy hinges on the timely and adequate regeneration of bone tissue in response to mechanical stimuli.To optimize clinical outcomes and prevent post-expansion relapse,we...The effectiveness of cranial suture expansion therapy hinges on the timely and adequate regeneration of bone tissue in response to mechanical stimuli.To optimize clinical outcomes and prevent post-expansion relapse,we delved into the underlying mechanisms governing bone remodeling during the processes of suture expansion and relapse.Our findings revealed that in vitro stretching bolstered mesenchymal stem cells'antioxidative and osteogenic capacity by orchestrating mitochondrial activities,which governed by force-induced endoplasmic reticulum(ER)stress.Nonetheless,this signal transduction occurred through the activation of protein kinase R-like ER kinase(PERK)at the ER-mitochondria interface,rather than ER-mitochondria calcium flow as previously reported.Subsequently,PERK activation triggered TFEB translocation to the nucleus,thus regulating mitochondrial dynamics transcriptionally.Assessment of the mitochondrial pool during expansion and relapse unveiled a sequential,two-phase regulation governed by the ER stress/p-PERK/TFEB signaling cascade.Initially,PERK activation facilitated TFEB nuclear localization,stimulating mitochondrial biogenesis through PGC1-α,thereby addressing energy demands during the initial phase.Subsequently,TFEB shifted focus towards ensuring adequate mitophagy for mitochondrial quality maintenance during the remodeling process.Premature withdrawal of expanding force disrupted this sequential regulation,leading to compromised mitophagy and the accumulation of dysfunctional mitochondria,culminating in suboptimal bone regeneration and relapse.Notably,pharmacological activation of mitophagy effectively mitigated relapse and attenuated bone loss,while its inhibition impeded anticipated bone growth in remodeling progress.Conclusively,we elucidated the ER stress/p-PERK/TFEB signaling orchestrated sequential mitochondria biogenesis and mitophagy under mechanical stretch,thus ensuring antioxidative capacity and osteogenic potential of cranial suture tissues.展开更多
The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.Thi...The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.This study assessed the land subsidence before and after urban expansion in five areas of Lanzhou by using slope spectrum construction method and gradient expansion intensity measurement that integrated with SBAS-InSAR technology.The results show that construction land on slopes over 20°increased significantly,accounting for 16%of new construction land.The average slope spectrum index was 4.02,with the upper slope limit rising by 8.2°.The land subsidence rate threshold increased by 10 mm/a,and the proportion of pixels experiencing subsidence greater than 5 mm/year rose from 3.63%to 5.24%.Increased construction intensity on slopes caused higher and faster subsidence,which diminished with greater distance from the expansion areas.Areas with slopes between 10°and 25°saw the greatest acceleration in subsidence.Geological composition,building density,groundwater exploitation,and cut-and-fill thickness collectively influence land subsidence rates.This study provides a scientific basis for mitigating geological disaster risks and promoting safe urban development in mountainous cities.展开更多
For the people of Masaka,Kabuga and Muyumbu in Rwanda,the daily commute often takes longer than it should.A stretch of just 10 km along the Prince House-Giporoso-Masaka road can take half an hour during peak hours.The...For the people of Masaka,Kabuga and Muyumbu in Rwanda,the daily commute often takes longer than it should.A stretch of just 10 km along the Prince House-Giporoso-Masaka road can take half an hour during peak hours.The narrow two-lane artery,clogged with long-haul trucks from the Rwanda-Tanzania border and commuter traffic,has long tested the patience of drivers and pedestrians alike.In May,a long-awaited announcement finally arrived.Rwanda’s Ministry of Infrastructure confirmed plans to expand the road from two lanes to four,adding a 1.2-km flyover at Giporoso-Remera and an underpass to keep tra"c flowing smoothly.The$60.5 million(Rwf86 billion)project will be fully funded by China,a testament to the deepening friendship and cooperation between the two nations.For many residents,it signals the end of years of lost time and daily frustration.展开更多
TheγδT cells are an emerging class of immune effectors with potent antitumor activity,bridging innate and adaptive immunity.Their unique ability to recognise stress-induced ligands independently of major histocompat...TheγδT cells are an emerging class of immune effectors with potent antitumor activity,bridging innate and adaptive immunity.Their unique ability to recognise stress-induced ligands independently of major histocompatibility complex restriction makes them attractive candidates for cancer immunotherapy.However,the clinical application ofγδT cells requires efficient in vitro expansion strategies to generate large numbers of functional cells.This mini-review explores the latest advancements inγδT cell expansion protocols,focusing on key activation stimuli,cytokine support,and culture conditions that optimise proliferation and cytotoxicity.展开更多
MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and ser...MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.展开更多
Tomato is a model system for studying fleshy fruit development.After fertilization,cell division and expansion in the pericarp are crucial for fruit development and determine the final fruit size.TKN3 was found to be ...Tomato is a model system for studying fleshy fruit development.After fertilization,cell division and expansion in the pericarp are crucial for fruit development and determine the final fruit size.TKN3 was found to be expressed in the tomato ovary wall/pericarp of zero to two days post-anthesis fruits as a KNOX I class member,but its function in fruit development was elusive.Here,we found that mutations of TKN3 by CRISPR/Cas9 caused fruit developmental defects,and fruit weight was dramatically reduced in the tkn3cr mutant.Histological observation of fruit pericarps revealed that mutation of TKN3 repressed cell expansion after fertilization,leading to flattened cells in the mesocarp and thereby thinner pericarps in red fruits.Moreover,tkn3cr mutants also displayed pleiotropic phenotypes including enlarged leaves and floral organs,indicating conserved functions in meristem maintenance and leaf development.Yeast two-hybrid and BiFC assays further showed that TKN3 could interact with Solyc10g086640(a homolog of Arabidopsis PNY),which has a similar expression pattern as TKN3.Genome-wide identification of genes regulated by TKN3 indicated that the auxin and gibberellin(GA)pathways might mediate the function of TKN3.Our works revealed that TKN3 controls cell expansion in pericarps,and provides new insights into the roles of KNOX proteins in fruit development.展开更多
The clinical application of hepatocyte transplantation has been significantly hindered by the scarcity of primary hepatocytes and the functional immaturity of in vitro-pro-duced hepatocytes.By performing serial alloge...The clinical application of hepatocyte transplantation has been significantly hindered by the scarcity of primary hepatocytes and the functional immaturity of in vitro-pro-duced hepatocytes.By performing serial allogeneic hepatocyte transplantation in CRISPR/Cas9-mediated Fah-knockout pigs,we successfully achieved large-scale ex-pansion of hepatocytes while maintaining their authentic biological characteristics.Particularly,the established model enables sustained in vivo liver reconstruction,concurrently ameliorating hepatic fibrosis and demonstrating functional microenvi-ronmental remodeling.Moreover,through comprehensive single-cell transcriptomic profiling of 52418 hepatocytes across transplant generations(F0-F2),we discovered that the cellular composition of these transplanted hepatocytes is similar to that of wild-type hepatocytes.The regenerated liver exhibits all six major hepatic cell types identical to the wild-type counterparts,with the characteristic lobular zonation pat-terns well preserved.Our research provides valuable insights into the large-scale expansion of physiologically functional hepatocytes in vivo without compromising their biological properties.This finding holds great promise for advancing the clinical application of human hepatocyte transplantation,potentially offering more effective treatment options for patients with liver diseases.展开更多
Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb...Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb,respectively.The effects of microstructure,texture,crack propagation behavior and second phase precipitation behavior on hole expansion ratio were investigated.The precipitation behavior of TiC and(Ti,Nb)C in austenite and ferrite in three groups of steel samples was calculated theoretically.The results showed that the hole expansion ratios of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 51.73%,51.17%and 66.24%following simulated coiling at 600℃,respectively.The microstructure was mainly polygonal ferrite with a small amount of pearlite.The grain refinement of 0.097Ti–0.059Nb test steel and the low texture ratio of{110}//ND improved the hole expansion ratio.The low overall hole expansion ratio was due to the microstructure inhomogeneity.The microstructure uniformity was improved by the quenching and tempering treatment,and the hole expansion ratio of the three test steels was greatly increased.The fastest precipitation temperatures in the austenitic region of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 880,860 and 830℃,while those in the ferrite region were 680,675 and 675℃,respectively.The addition of Nb element increased the volume free energy,so that the critical core size of the nucleation on the dislocation line increased,resulting in the decrease in the fastest precipitation temperature.展开更多
Combining practical engineering projects, this article analyzes the design strategies for the reconstruction and expansion of insufficient clearance sections in highway interchanges. This includes an overview of the p...Combining practical engineering projects, this article analyzes the design strategies for the reconstruction and expansion of insufficient clearance sections in highway interchanges. This includes an overview of the project, a comparison of design options for insufficient clearance in interchanges, and the main design strategies for reconstruction and expansion. It is hoped that this analysis can provide a reference for the design of such road reconstruction and expansion projects.展开更多
BACKGROUND Hematoma expansion(HE)typically portends a poor prognosis in spontaneous intracerebral hemorrhage(ICH).Several radiographic and laboratory values have been proposed as predictive markers of HE.AIM To perfor...BACKGROUND Hematoma expansion(HE)typically portends a poor prognosis in spontaneous intracerebral hemorrhage(ICH).Several radiographic and laboratory values have been proposed as predictive markers of HE.AIM To perform a systematic review and meta-analysis on the association of neu-trophil-to-lymphocyte ratio(NLR)and HE in ICH.A secondary outcome exa-mined was the association of NLR and perihematomal(PHE)growth.METHODS Three databases were searched(PubMed,EMBASE,and Cochrane)for studies evaluating the effect of NLR on HE and PHE growth.The inverse variance me-thod was applied to estimate an overall effect for each specific outcome by combining weighted averages of the individual studies’estimates of the logarithm odds ratio(OR).Given heterogeneity of the studies,a random effect was applied.Risk of bias was analyzed using the Newcastle-Ottawa Scale.The study was conducted following the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines.The protocol was registered in PROSPERO(No.CRD42024549924).RESULTS Eleven retrospective cohort studies involving 2953 patients were included in the meta-analysis.Among those,HE was investigated in eight studies,whereas PHE growth was evaluated in three.Blood sample was obtained on admission in ten studies,and at 24 hours in one study.There was no consensus on cut-off value among the studies.NLR was found to be significantly associated with higher odds of HE(OR=1.09,95%CI:1.04-1.15,I2=86%,P<0.01),and PHE growth(OR=1.28,95%CI:1.19-1.38,I2=0%,P<0.01).Qualitative analysis of each outcome revealed overall moderate risk of bias mainly due to lack of control for systemic confounders.CONCLUSION The available literature suggests that a possible association may exist between NLR on admission and HE,and PHE growth.Future studies controlled for systemic confounders should be designed to consolidate this finding.If confirmed,NLR could be added as a readily available and inexpensive biomarker to identify a subgroup of patients at higher risk of developing HE.展开更多
The first experiments on laser-driven cylindrical gold foam hohlraums have been performed at the 100 kJ SG-Ⅲ laser facility.Measurements of the expanding plasma emission show that there is less expanding plasma fill ...The first experiments on laser-driven cylindrical gold foam hohlraums have been performed at the 100 kJ SG-Ⅲ laser facility.Measurements of the expanding plasma emission show that there is less expanding plasma fill in foam hohlraums with a wall density of 0.8 g/cm^(3) than in solid gold hohlraums.The radiation temperatures at different angles confirm these results.Simulation results show that the expanding plasma density in the foam hohlraums is lower than in the solid hohlraums,resulting in less expanding plasma emission and higher radiation temperature.Thus,foam gold hohlraums have advantages in reducing wall plasma filling and improving X-ray transmission,which has potential applications in achieving a higher fusion yield.展开更多
Because of the large coefficient of thermal expansion (CTE) (23 ppm K^(–1)), aluminum faces challenges in meeting the demands of high dimensional stability in precision instruments, microelectronics, and aerospace. F...Because of the large coefficient of thermal expansion (CTE) (23 ppm K^(–1)), aluminum faces challenges in meeting the demands of high dimensional stability in precision instruments, microelectronics, and aerospace. Filling negative thermal expansion (NTE) particles into aluminum can create composites with either zero or low CTEs. However, the resulting composites usually have poor thermal conductivity due to their monolithic configuration, i.e., the NTE particles are filled randomly. Thus, heat sinks should be equipped to assist their usage (e.g., in thermal management). This in turn causes strong thermal stress in the packaging system owing to the high contrast in the CTEs between those monolithic composites and heat sinks typically made of copper or aluminum. Here, we propose a gradient configuration for low-CTE aluminum composite, inspired by the bamboo structure. The gradient distribution of NTE particles (Zn_(0.5)Sn_(0.3)Mn_(0.2)NMn_(3), ZSM) was obtained by laying up several layers of ZSM/Al with the ZSM fraction ranging from 0 to 28 vol.%. In the gradient composite, the CTE near room temperature varies from 3.4 pm K^(–1) on one side to 21 ppm K^(–1) on the other side. Such a gradient CTE distribution would facilitate the low-thermal-stress designs and thus help stabilize the dimension of a precision system. Furthermore, this composite has a high thermal conductivity of 130 W m^(–1) K^(–1) and strong toughness when the flexural loading is applied on the 28 vol.% ZSM/Al side. Our research provides a novel approach to designing metallic matrix composites with unprecedented performance.展开更多
基金financially supported by National Natural Science Foundation of China(No.52175321)the Fund of Key Laboratory of High Temperature Electromagnetic Materials and Structure of MOE(No.KB202505)。
文摘There is an urgent need to develop magnesium-matrix materials that exhibit both high thermal conductivity and low thermal expansion to ensure compatibility with chips.This study aims to develop a Mg-Zn-Cu alloy with high thermal conductivity.Furthermore,it explores the preparation of AlN_(P)/Mg-Zn-Cu composites featuring low coefficients of thermal expansion.The stir casting method was utilized to fabricate the composites and an investigation was conducted to examine their microstructure and thermal properties.Results indicate that the addition of AlN_(P)reduces the thermal expansion coefficient while maintaining relatively high thermal conductivity.Specifically,the AlN_(P)/Mg-0.5Zn-0.5Cu composite with 30wt.%AlN_(P)achieves a thermal conductivity of 132.7 W·m^(-1)·K^(-1)and a thermal expansion coefficient of 18.5×10^(-6)K^(-1),rendering it suitable for electronic packaging applications where thermal management is critical.
基金National Key R&D Program of China(2022YFB2602900)R&D Fund Project of China Academy of Railway Sciences Corporation Limited(2021YJ084)+2 种基金Project of Science and Technology R&D Program of China Railway(2016G002-K)R&D Fund Project of China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.(2021)R&D Fund Project of China Railway Shanghai Group(2021141).
文摘Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the approach bridge.For long-span railway bridges,it must also be coordinated with rail expansion joint(REJ),which is necessary to accommodate the expansion and contraction of,and reducing longitudinal stress in,the rails.The main aim of this study is to present analysis of recent developments in the research and application of BEJs in high-speed railway(HSR)long-span bridges in China,and to propose a performance-based integral design method for BEJs used with REJs,from both theoretical and engineering perspectives.Design/methodology/approach–The study first presents a summary on the application and maintenance of BEJs in HSR long-span bridges in China representing an overview of their state of development.Results of a survey of typical BEJ faults were analyzed,and field testing was conducted on a railway cable-stayed bridge in order to obtain information on the major mechanical characteristics of its BEJ under train load.Based on the above,a performance-based integral design method for BEJs with maximum expansion range 1600 mm(±800 mm),was proposed,covering all stages from overall conceptual design to consideration of detailed structural design issues.The performance of the novel BEJ design thus derived was then verified via theoretical analysis under different scenarios,full-scale model testing,and field testing and commissioning.Findings–Two major types of BEJs,deck-type and through-type,are used in HSR long-span bridges in China.Typical BEJ faults were found to mainly include skewness of steel sleepers at the bridge gap,abnormally large longitudinal frictional resistance,and flexural deformation of the scissor mechanisms.These faults influence BEJ functioning,and thus adversely affect track quality and train running performance at the beam end.Due to their simple and integral structure,deck-type BEJs with expansion range 1200 mm(±600 mm)or less have been favored as a solution offering improved operational conditions,and have emerged as a standard design.However,when the expansion range exceeds the above-mentioned value,special design work becomes necessary.Therefore,based on engineering practice,a performance-based integral design method for BEJs used with REJs was proposed,taking into account four major categories of performance requirements,i.e.,mechanical characteristics,train running quality,durability and insulation performance.Overall BEJ design must mainly consider component strength and the overall stiffness of BEJ;the latter factor in particular has a decisive influence on train running performance at the beam end.Detailed BEJ structural design must stress minimization of the frictional resistance of its sliding surface.The static and dynamic performance of the newlydesigned BEJ with expansion range 1600 mm have been confirmed to be satisfactory,via numerical simulation,full-scale model testing,and field testing and commissioning.Originality/value–This research provides a broad overview of the status of BEJs with large expansion range in HSR long-span bridges in China,along with novel insights into their design.
基金supported by the National Natural Science Foundation of China(52476200,52106244)the Guangdong Basic and Applied Basic Research Foundation(2024A1515030124)+1 种基金the Science and Technology Project of China Southern Power Grid under Grant GDKJXM20230246(030100KC23020017)the Fundamental Research Funds for the Central Universities。
文摘Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the degradation behavior and failure mechanism of various overcharged states(100%SOC,105%SOC,110%SOC,and 115%SOC),multiple advanced in-situ characterization techniques(accelerating rate calorimeter,electrochemical impedance spectroscopy,ultrasonic scanning,and expansion instrument)were utilized.Additionally,re-overcharge-induced thermal runaway(TR)tests were conducted,with a specific emphasis on the evolution of the expansion force signal.Results indicated significant degradation at 110%SOC including conductivity loss,loss of lithium inventory,and loss of active material accompanied by internal gas generation.These failure behaviors slow down the expansion force rate during reovercharging,reducing the efficacy of active warnings that depend on rate thresholds of expansion force.Specifically,the warning time for 115%SOC battery is only 144 s,which is 740 s shorter than that for fresh battery,and the time to TR is advanced by 9 min.Moreover,the initial self-heating temperature(T1)is reduced by 62.4℃compared to that of fresh battery,reaching only 70.8℃.To address the low safety of overcharged batteries,a passive overcharge warning method utilizing relaxation expansion force was proposed,based on the continued gas generation after stopping charging,leading to a sustained increase in force.Compared to active methods that rely on thresholds of expansion force rate,the passive method can issue warnings 115 s earlier.By combining the passive and active warning methods,guaranteed effective overcharge warning can be issued 863-884 s before TR.This study introduces a novel perspective for enhancing the safety of batteries.
基金National Natural Science Foundation of China(Nos.42171130 and 42301158)Pilot Project of China’s Strength in Transportation for the Central Research Institute(No.QG2021-1-4-7)National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2021YFB2601200).
文摘Sulfate attack-induced expansion of cement-treated aggregates in seasonally frozen regions is a well-known issue which causes continuous expansion in railway subgrades,and particularly in high-speed railways.Accordingly,we investigated the influence of material proportions,the number of freeze-thaw(FT)cycles,and temperature gradients on the expansion mechanism of sulfate attack on cement-treated aggregates subjected to FT cycles.The conditions,laws,and dominant factors causing the expansion of aggregates were analyzed through swelling tests.The results indicate that under FT cycles,3%content cement-treated graded macadam only experiences slight deformation.The maximum strain of graded macadam attacked by 1%sodium sulfate content in each FT cycle is significantly larger than that of 3%content cement-treated graded macadam attacked by 1%sodium sulfate content.Using scanning electron microscopy,needle-like crystals were observed during sulfate attack of cement-treated graded macadam.Through quantitative analysis,we determined the recoverable and unrecoverable deformations of graded macadam under FT cycles.For graded macadam under sulfate attack,the expansion is mainly induced by periodic frost heave and salt expansion,as well as salt migration.For cement-treated graded macadam under sulfate attack,the expansion is mainly induced by chemical attack and salt migration.This study can serve as a reference for future research on the mechanics of sulfate attack on cement-treated aggregates that experience FT cycles,and provide theoretical support for methods that remediate the expansion induced by sulfate attack.
基金supported by the research project within the program“Excellence Initiative-Research University”for the AGH University of Krakow(IDUB AGH,Action 21)Kun Zheng acknowledges financial support from AGH University of Krakow(No.16.16.210.476).
文摘Minimizing the thermal expansion coefficient(TEC)mismatch between the cathode and electrolyte in solid oxide fuel cells is crucial for achieving stable,durable operation and high performance.Recently,materials with negative thermal expansion(NTE)have at-tracted significant attention as effective additives for tailoring the thermomechanical properties of electrodes and enhancing cell durability.In this work,for the first time,single-phase NTE perovskite Sm_(0.85)Zn_(0.15)MnO_(3−δ)(SZM15)was successfully synthesized via the sol-gel method,eliminating the unwanted ZnO phase typically observed in materials obtained through the conventional solid-state reaction route.The sol-gel approach proved highly advantageous,offering low cost,robustness,excellent chemical homogeneity,precise compositional control,and high phase purity.After optimization of synthesis parameters,a negative TEC of approximately−6.5×10^(−6)K^(−1)was achieved in the 400-850℃range.SZM15 was then incorporated as an additive(10wt%-50wt%)into a SmBa0.5Sr0.5CoCuO_(5+δ)(SBSCCO)cathode to tune the thermomechanical properties with a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ)(LSGM)electrolyte,achieving a minimal TEC mismatch of only 1%.Notably,the SBSCCO+10wt%SZM15 composite cathode exhibited the lowest polarization resistance of 0.019Ω·cm^(2)at 900℃,showing approximately 70%lower than that of the pristine cathode.Excellent long-term stability after 100 h of operation was achieved.In addition,a high peak power density of 680 mW·cm^(−2)was achieved in a Ni-YSZ(yttria-stabilized zirconia)|YSZ|Ce_(0.9)Gd_(0.1)O_(2−δ)(GDC10)|SBSCCO+10wt%SZM15 anode-supported fuel cell at 850℃,highlighting the effectiveness of incorporating NTE materials as a promising strategy for regulating the thermomechanical properties and improving the long-term stability of intermediate temperature solid oxide fuel cells(IT-SOFCs).
基金financially supported by the National Natural Science Foundation of China(Nos.22271309,12425403 and 12261131499)the National Key R&D Program of China(No.2021YFA1400300)+2 种基金financial support from the Science and Technology Development Fund from Macao SAR(No.0062/2023/ITP2)Macao Polytechnic University(No.RP/FCA-03/2023)Synchrotron X-ray powder diffraction experiments were conducted at SPring-8,approved by the Japan Synchrotron Radiation Research Institute(Nos.2024A1506,2024A1695 and 2024B1807)
文摘Negative thermal expansion(NTE)is a notable physical property where a material’s volume decreases instead of increasing when heated.The identification of NTE materials is crucial for thermal expansion control engineering.Most NTE materials exhibit NTE only within a narrow temperature range,restricting their applications.Achieving NTE across a broad temperature range remains a significant challenge.This study developed a novel PbTiO_(3)-based system,(1-x)PbTiO_(3–x)BiLuO_(3),incorporating rare-earth elements,using a distinctive high-pressure and high-temperature synthesis technique.We achieved NTE across a broad temperature range by coupling lattice(c/a)with ferroelectric order parameters.The incorporation of BiLuO_(3)resulted in distinctive ferroelectric characteristics,including increased tetragonality,spontaneous polarization,and NTE over a broad temperature range.NTE over an extended temperature range has been achieved in 0.95PbTiO_(3)–0.05BiLuO_(3)(■=−1.7×10^(–5)K^(−1),300–840 K)and 0.90PbTiO_(3)–0.10BiLuO_(3)(■=−1.4×10^(–5)K^(−1),300–860 K),compared to pristine PbTiO_(3)(■=−1.99×10^(–5)K^(−1),300–763 K).The improved tetragonalities and broader NTE temperature range result from the strong hybridization of Pb/Bi–O and Ti/Lu–O atoms,as demonstrated by combined experimental and theoretical analyses,including high-energy synchrotron X-ray diffraction,Raman spectroscopy,and density functional theory calculations.This study introduces a novel example of NTE over a broad temperature range,highlighting its potential as a high-performance thermal expansion compensator.Additionally,it presents an effective method for incorporating rare-earth elements to achieve NTE in PbTiO_(3)-based perovskites across a wide temperature range.
基金supported by the Fundamental Research Funds for the Central Universities(WK2090000055)Anhui Provincial Natural Science Foundation of China(2308085QG231).
文摘As a negative electrode material for lithium-ion batteries,silicon monoxide(SiO)suffers from dramatic volume changes during cycling,causing excessive stress within the electrode and resulting in electrode deformation and fragmentation.This ultimately leads to a decrease in cell capacity.The trends of volume expansion and capacity change of the SiO/graphite(SiO/C)composite electrode during cycling were investigated via in situ expansion monitoring.First,a series of expansion test schemes were designed,and the linear relationship between negative electrode expansion and cell capacity degradation was quantitatively analyzed.Then,the effects of different initial pressures on the long-term cycling performance of the cell were evaluated.Finally,the mechanism of their effects was analyzed by scanning electron microscope.The results show that after 50 cycles,the cell capacity decreases from 2.556 mAh to 1.689 mAh,with a capacity retention ratio(CRR)of only 66.08%.A linear relationship between the capacity retention ratio and thickness expansion was found.Electrochemical measurements and scanning electron microscope images demonstrate that intense stress inhibits the lithiation of the negative electrode and that the electrode is more susceptible to irreversible damage during cycling.Overall,these results reveal the relationship between the cycling performance of SiO and the internal pressure of the electrode from a macroscopic point of view,which provides some reference for the application of SiO/C composite electrodes in lithium-ion batteries.
基金Supported by Projects from Chongqing Municipal Science and Technology Commission(CSTB2022NSCQ-MSX0445)。
文摘For the Sylvester continued fraction expansions of real numbers,FAN et al.(2007)proved that,for almost all real numbers,the nth partial quotient grows exponentially with respect to the product of the first n-1 partial quotients.In this paper,we establish the Hausdorff dimension of the exceptional set where the growth rate is a general function.
基金supported by National Natural Science Foundation of China(No.82370988,32271416,81870743,82170934)Sichuan Province Science and Technology Support Program(2024YFHZ0043)。
文摘The effectiveness of cranial suture expansion therapy hinges on the timely and adequate regeneration of bone tissue in response to mechanical stimuli.To optimize clinical outcomes and prevent post-expansion relapse,we delved into the underlying mechanisms governing bone remodeling during the processes of suture expansion and relapse.Our findings revealed that in vitro stretching bolstered mesenchymal stem cells'antioxidative and osteogenic capacity by orchestrating mitochondrial activities,which governed by force-induced endoplasmic reticulum(ER)stress.Nonetheless,this signal transduction occurred through the activation of protein kinase R-like ER kinase(PERK)at the ER-mitochondria interface,rather than ER-mitochondria calcium flow as previously reported.Subsequently,PERK activation triggered TFEB translocation to the nucleus,thus regulating mitochondrial dynamics transcriptionally.Assessment of the mitochondrial pool during expansion and relapse unveiled a sequential,two-phase regulation governed by the ER stress/p-PERK/TFEB signaling cascade.Initially,PERK activation facilitated TFEB nuclear localization,stimulating mitochondrial biogenesis through PGC1-α,thereby addressing energy demands during the initial phase.Subsequently,TFEB shifted focus towards ensuring adequate mitophagy for mitochondrial quality maintenance during the remodeling process.Premature withdrawal of expanding force disrupted this sequential regulation,leading to compromised mitophagy and the accumulation of dysfunctional mitochondria,culminating in suboptimal bone regeneration and relapse.Notably,pharmacological activation of mitophagy effectively mitigated relapse and attenuated bone loss,while its inhibition impeded anticipated bone growth in remodeling progress.Conclusively,we elucidated the ER stress/p-PERK/TFEB signaling orchestrated sequential mitochondria biogenesis and mitophagy under mechanical stretch,thus ensuring antioxidative capacity and osteogenic potential of cranial suture tissues.
基金National Natural Science Foundation of China(Grant No.42271214)National Key R&D Program of China(Grant No.2022YFC3800700)+1 种基金Key Research Program of Gansu Province(Grant No.23ZDKA0004)Natural Science Foundation of Gansu Province(Grant No.21JR7RA281).
文摘The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.This study assessed the land subsidence before and after urban expansion in five areas of Lanzhou by using slope spectrum construction method and gradient expansion intensity measurement that integrated with SBAS-InSAR technology.The results show that construction land on slopes over 20°increased significantly,accounting for 16%of new construction land.The average slope spectrum index was 4.02,with the upper slope limit rising by 8.2°.The land subsidence rate threshold increased by 10 mm/a,and the proportion of pixels experiencing subsidence greater than 5 mm/year rose from 3.63%to 5.24%.Increased construction intensity on slopes caused higher and faster subsidence,which diminished with greater distance from the expansion areas.Areas with slopes between 10°and 25°saw the greatest acceleration in subsidence.Geological composition,building density,groundwater exploitation,and cut-and-fill thickness collectively influence land subsidence rates.This study provides a scientific basis for mitigating geological disaster risks and promoting safe urban development in mountainous cities.
文摘For the people of Masaka,Kabuga and Muyumbu in Rwanda,the daily commute often takes longer than it should.A stretch of just 10 km along the Prince House-Giporoso-Masaka road can take half an hour during peak hours.The narrow two-lane artery,clogged with long-haul trucks from the Rwanda-Tanzania border and commuter traffic,has long tested the patience of drivers and pedestrians alike.In May,a long-awaited announcement finally arrived.Rwanda’s Ministry of Infrastructure confirmed plans to expand the road from two lanes to four,adding a 1.2-km flyover at Giporoso-Remera and an underpass to keep tra"c flowing smoothly.The$60.5 million(Rwf86 billion)project will be fully funded by China,a testament to the deepening friendship and cooperation between the two nations.For many residents,it signals the end of years of lost time and daily frustration.
基金Supported by National Science Center of Poland,No.2019/35/N/NZ6/02973.
文摘TheγδT cells are an emerging class of immune effectors with potent antitumor activity,bridging innate and adaptive immunity.Their unique ability to recognise stress-induced ligands independently of major histocompatibility complex restriction makes them attractive candidates for cancer immunotherapy.However,the clinical application ofγδT cells requires efficient in vitro expansion strategies to generate large numbers of functional cells.This mini-review explores the latest advancements inγδT cell expansion protocols,focusing on key activation stimuli,cytokine support,and culture conditions that optimise proliferation and cytotoxicity.
基金supported by the National Natural Science Foundation of China(Nos.52102088 and 22075026)support from Teli Fellowship,Beijing Institute of Technology,and facility support from Analysis&Testing Center,and Experimental Center of Materials Sciences&Engineering at Beijing Institute of Technology.
文摘MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.
基金supported by The National Key Research and Development Program of China(Grant No.2022YFF1003002)the National Natural Science Foundation of China(Grant No.32120103010)the Project of Yuandu Industry Leading talent。
文摘Tomato is a model system for studying fleshy fruit development.After fertilization,cell division and expansion in the pericarp are crucial for fruit development and determine the final fruit size.TKN3 was found to be expressed in the tomato ovary wall/pericarp of zero to two days post-anthesis fruits as a KNOX I class member,but its function in fruit development was elusive.Here,we found that mutations of TKN3 by CRISPR/Cas9 caused fruit developmental defects,and fruit weight was dramatically reduced in the tkn3cr mutant.Histological observation of fruit pericarps revealed that mutation of TKN3 repressed cell expansion after fertilization,leading to flattened cells in the mesocarp and thereby thinner pericarps in red fruits.Moreover,tkn3cr mutants also displayed pleiotropic phenotypes including enlarged leaves and floral organs,indicating conserved functions in meristem maintenance and leaf development.Yeast two-hybrid and BiFC assays further showed that TKN3 could interact with Solyc10g086640(a homolog of Arabidopsis PNY),which has a similar expression pattern as TKN3.Genome-wide identification of genes regulated by TKN3 indicated that the auxin and gibberellin(GA)pathways might mediate the function of TKN3.Our works revealed that TKN3 controls cell expansion in pericarps,and provides new insights into the roles of KNOX proteins in fruit development.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFA0805905,2023YFC3404305 and 2024YFA1107900the Strategic Priority Research Program of the Chinese Academy of Sciences,Grant/Award Number:XDB1150000+1 种基金the CAS Project for Young Scientists in Basic Research,Grant/Award Number:YSBR-012Bingtuan Science and Technology Project,Grant/Award Number:NYHXGG2023AA01。
文摘The clinical application of hepatocyte transplantation has been significantly hindered by the scarcity of primary hepatocytes and the functional immaturity of in vitro-pro-duced hepatocytes.By performing serial allogeneic hepatocyte transplantation in CRISPR/Cas9-mediated Fah-knockout pigs,we successfully achieved large-scale ex-pansion of hepatocytes while maintaining their authentic biological characteristics.Particularly,the established model enables sustained in vivo liver reconstruction,concurrently ameliorating hepatic fibrosis and demonstrating functional microenvi-ronmental remodeling.Moreover,through comprehensive single-cell transcriptomic profiling of 52418 hepatocytes across transplant generations(F0-F2),we discovered that the cellular composition of these transplanted hepatocytes is similar to that of wild-type hepatocytes.The regenerated liver exhibits all six major hepatic cell types identical to the wild-type counterparts,with the characteristic lobular zonation pat-terns well preserved.Our research provides valuable insights into the large-scale expansion of physiologically functional hepatocytes in vivo without compromising their biological properties.This finding holds great promise for advancing the clinical application of human hepatocyte transplantation,potentially offering more effective treatment options for patients with liver diseases.
基金financially supported by the CITIC niobium steel development award Fund(M1656-2021)Central Iron and Steel Research Institute for its independent research and development fund(No.21G62460ZD).
文摘Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb,respectively.The effects of microstructure,texture,crack propagation behavior and second phase precipitation behavior on hole expansion ratio were investigated.The precipitation behavior of TiC and(Ti,Nb)C in austenite and ferrite in three groups of steel samples was calculated theoretically.The results showed that the hole expansion ratios of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 51.73%,51.17%and 66.24%following simulated coiling at 600℃,respectively.The microstructure was mainly polygonal ferrite with a small amount of pearlite.The grain refinement of 0.097Ti–0.059Nb test steel and the low texture ratio of{110}//ND improved the hole expansion ratio.The low overall hole expansion ratio was due to the microstructure inhomogeneity.The microstructure uniformity was improved by the quenching and tempering treatment,and the hole expansion ratio of the three test steels was greatly increased.The fastest precipitation temperatures in the austenitic region of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 880,860 and 830℃,while those in the ferrite region were 680,675 and 675℃,respectively.The addition of Nb element increased the volume free energy,so that the critical core size of the nucleation on the dislocation line increased,resulting in the decrease in the fastest precipitation temperature.
文摘Combining practical engineering projects, this article analyzes the design strategies for the reconstruction and expansion of insufficient clearance sections in highway interchanges. This includes an overview of the project, a comparison of design options for insufficient clearance in interchanges, and the main design strategies for reconstruction and expansion. It is hoped that this analysis can provide a reference for the design of such road reconstruction and expansion projects.
文摘BACKGROUND Hematoma expansion(HE)typically portends a poor prognosis in spontaneous intracerebral hemorrhage(ICH).Several radiographic and laboratory values have been proposed as predictive markers of HE.AIM To perform a systematic review and meta-analysis on the association of neu-trophil-to-lymphocyte ratio(NLR)and HE in ICH.A secondary outcome exa-mined was the association of NLR and perihematomal(PHE)growth.METHODS Three databases were searched(PubMed,EMBASE,and Cochrane)for studies evaluating the effect of NLR on HE and PHE growth.The inverse variance me-thod was applied to estimate an overall effect for each specific outcome by combining weighted averages of the individual studies’estimates of the logarithm odds ratio(OR).Given heterogeneity of the studies,a random effect was applied.Risk of bias was analyzed using the Newcastle-Ottawa Scale.The study was conducted following the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines.The protocol was registered in PROSPERO(No.CRD42024549924).RESULTS Eleven retrospective cohort studies involving 2953 patients were included in the meta-analysis.Among those,HE was investigated in eight studies,whereas PHE growth was evaluated in three.Blood sample was obtained on admission in ten studies,and at 24 hours in one study.There was no consensus on cut-off value among the studies.NLR was found to be significantly associated with higher odds of HE(OR=1.09,95%CI:1.04-1.15,I2=86%,P<0.01),and PHE growth(OR=1.28,95%CI:1.19-1.38,I2=0%,P<0.01).Qualitative analysis of each outcome revealed overall moderate risk of bias mainly due to lack of control for systemic confounders.CONCLUSION The available literature suggests that a possible association may exist between NLR on admission and HE,and PHE growth.Future studies controlled for systemic confounders should be designed to consolidate this finding.If confirmed,NLR could be added as a readily available and inexpensive biomarker to identify a subgroup of patients at higher risk of developing HE.
基金support from the National Natural Science Foundation of China(Grant Nos.11775204 and 12105269)the Presidential Foundation of the China Academy of Engineering Physics(Grant No.YZJJLX2018011)。
文摘The first experiments on laser-driven cylindrical gold foam hohlraums have been performed at the 100 kJ SG-Ⅲ laser facility.Measurements of the expanding plasma emission show that there is less expanding plasma fill in foam hohlraums with a wall density of 0.8 g/cm^(3) than in solid gold hohlraums.The radiation temperatures at different angles confirm these results.Simulation results show that the expanding plasma density in the foam hohlraums is lower than in the solid hohlraums,resulting in less expanding plasma emission and higher radiation temperature.Thus,foam gold hohlraums have advantages in reducing wall plasma filling and improving X-ray transmission,which has potential applications in achieving a higher fusion yield.
基金supported by the National Natural Foundation of China(No.52171146)the HFIPS Director's Fund(No.BJPY2023A08)the Natural Science Foundation of Anhui Province(No.2108085ME145).
文摘Because of the large coefficient of thermal expansion (CTE) (23 ppm K^(–1)), aluminum faces challenges in meeting the demands of high dimensional stability in precision instruments, microelectronics, and aerospace. Filling negative thermal expansion (NTE) particles into aluminum can create composites with either zero or low CTEs. However, the resulting composites usually have poor thermal conductivity due to their monolithic configuration, i.e., the NTE particles are filled randomly. Thus, heat sinks should be equipped to assist their usage (e.g., in thermal management). This in turn causes strong thermal stress in the packaging system owing to the high contrast in the CTEs between those monolithic composites and heat sinks typically made of copper or aluminum. Here, we propose a gradient configuration for low-CTE aluminum composite, inspired by the bamboo structure. The gradient distribution of NTE particles (Zn_(0.5)Sn_(0.3)Mn_(0.2)NMn_(3), ZSM) was obtained by laying up several layers of ZSM/Al with the ZSM fraction ranging from 0 to 28 vol.%. In the gradient composite, the CTE near room temperature varies from 3.4 pm K^(–1) on one side to 21 ppm K^(–1) on the other side. Such a gradient CTE distribution would facilitate the low-thermal-stress designs and thus help stabilize the dimension of a precision system. Furthermore, this composite has a high thermal conductivity of 130 W m^(–1) K^(–1) and strong toughness when the flexural loading is applied on the 28 vol.% ZSM/Al side. Our research provides a novel approach to designing metallic matrix composites with unprecedented performance.
