The working environment of aerospace engines is extremely harsh with temperature exceeding 1700℃and accompanied by thermal coupling effects.In this condition,the materials employed in hypersonic aircraft undergo abla...The working environment of aerospace engines is extremely harsh with temperature exceeding 1700℃and accompanied by thermal coupling effects.In this condition,the materials employed in hypersonic aircraft undergo ablation issues,which can cause catastrophic accidents.Due to the excellent high-temperature stability and ablation resistance,HfC exhibits outstanding thermal expansion coefficient matching that of C/SiC composites.2.5D needle-punched C/SiC composites coated with HfC are prepared using a plasma spraying process,and a high-enthalpy arc-heated wind tunnel is employed to simulate the re-entry environment of aircraft at 8 Mach and an altitude of 32 km.The plasma-sprayed HfC-coated 2.5D needle-punched C/SiC composites are subjected to long-term dynamic testing,and their properties are investigated.Specifically,after the thermal assessment ablation experiment,the composite retains its overall structure and profile;the total mass ablation rate is 0.07445 g/s,the average linear ablation rate in the thickness direction is-0.0675μm/s,and the average linear ablation rate in the length direction is 13.907μm/s.Results verify that plasma-sprayed HfC coating exhibits excellent anti-oxidation and ablation resistance properties.Besides,the microstructure and ablation mechanism of the C/SiC composites are studied.It is believed that this work will offer guideline for the development of thermal protection materials and the assessment of structural thermal performance.展开更多
The influence of the processing parameters on the properties of needle-punched composite geotextiles,compounded by polypropylene filament woven-fabrics and nonwoven fabrics is studied by using orthogonal design method...The influence of the processing parameters on the properties of needle-punched composite geotextiles,compounded by polypropylene filament woven-fabrics and nonwoven fabrics is studied by using orthogonal design method. The relationship between tensile strength and peeling strength is discussed. The experimental results are offered as reference.展开更多
A series of confined swell tests were conducted on a needle-punched geosynthetic clay liner (GCL) with tap water as the hydration medium. The effects of the static confining stress on the swelling characteristics of G...A series of confined swell tests were conducted on a needle-punched geosynthetic clay liner (GCL) with tap water as the hydration medium. The effects of the static confining stress on the swelling characteristics of GCLs and the hydration time under different confining stresses were explored. Increasing the static confining stress led to: shorter hydration time; smaller final GCL height; less final GCL bulk void ratio; smaller final bentonite moisture content. The confined swell pressure determined for the tested GCL was 82.2 kPa, and the relationships between confining stress, final bulk void ratio (or final GCL height, final bentonite moisture content) were attained through the analyses of the confined swell test results in this study.展开更多
Improving the osteogenic properties of bone grafts plays a critical role in the repair and functional restoration of critical-sized bone defects.The endogenous electric field,one of the most crucial physiological sign...Improving the osteogenic properties of bone grafts plays a critical role in the repair and functional restoration of critical-sized bone defects.The endogenous electric field,one of the most crucial physiological signals,has been confirmed to maintain physiological function and reconstruct the structure of bone,which is inadequate in bone defect sites.Strategies for the devel-opment of electroactive osteogenic biomaterials arise to remodel and promote the electrophysiological microenvironment.Among the electroactive materials,electret biomaterials can provide a stable and persistent endogenous electrical stimulation,which better conforms to the physiological microenvironment and has long-term effectiveness in the bone repair process.Herein,an electret hybrid electrospun fibrous mat(EHFM)was developed to mimic the structure of the natural extracellular matrix(ECM)with a suitable and persistent electrophysiological microenvironment.The EHFM was constructed with a core-shell structure,in which silicon dioxide electrets were loaded in the core-layer to remodel and maintain the electrical microenvironment over the long term.The EHFM significantly promoted the osteogenesis of bone mesenchymal stem cells(BMSCs)in vitro and showed remarkable ability in bone repair,which was three times better than that of the control group in a critical-sized rat calvarial defect model.Furthermore,it was verified that EHFM-derived osteogenesis was related to the activation of the calcium ion-sensing receptor(CaSR),while increasing intracellular calcium ion concentration of BMSCs.This study puts forward a novel engineering strategy to promote bone defect repair by remodeling a stable and persistent electrophysiological microenvironment,showing potential for clinical applications.展开更多
Developing an advanced individual protection cloth is a pivotal factor in combating global pathogen epidemics.However,formidable challenges are posed by the triangularity imbalance effect,necessitating the simultaneou...Developing an advanced individual protection cloth is a pivotal factor in combating global pathogen epidemics.However,formidable challenges are posed by the triangularity imbalance effect,necessitating the simultaneous fulfillment of require-ments for high comfort,high safety,and mass production.In this study,a mass-producible hybrid polytetrafluoroethylene nanofiber mat(HPNFM)was developed by integrating technologies of organic-inorganic hybridization and membrane asynchronous stretching.Exceptional comfort was attained by conferring waterproofing and breathability attributes,achieved through the radial island-chain architecture exhibiting hydrophobicity and nanoporosity.Furthermore,through the incorpo-ration of high-efficiency anti-pathogen nanoparticles,the HPNFM ensures high safety,demonstrating active antibacterial and antiviral effects.This is achieved through the synergistic effects of electrostatic induction and reactive oxygen species-based pathogen inactivation.More significantly,an HPNFM-based individual protective suit is designed and manufactured,which successfully encapsulates the advantages of high comfort,safety,and mass production,displaying competitiveness as a commercial product.Positioned as a viable strategy,this work holds substantial potential for practical applications in responding to future epidemics.展开更多
A stable surface to move manpower and equipment is a key for the construction operations. To create a stable road surface, the road construction techniques are time-consuming and expensive for a traditional constructi...A stable surface to move manpower and equipment is a key for the construction operations. To create a stable road surface, the road construction techniques are time-consuming and expensive for a traditional construction which requires compaction of soil, aggregate base, sub-base and asphaltic layers. A Geosynthetic Access Mat (GAM) system can serve as an alternative to other traditional construction techniques to accommodate temporary construction. Due to its rigidity, the mat system can provide substantial vertical resistance to the applied load under a large deflection subject to soil conditions. This paper provides details of GAM specifications, soil conditions, applications, installation procedure, comparison with other soil stabilization methods and Aramco experience for deployments of these mats.展开更多
冠突散囊菌(Eurotium cristatum)闭囊壳的产生和数量受各种与有性产孢相关的基因控制,而MAT基因(Mating type gene,MAT)是其中的关键基因之一,为调查MAT基因在冠突散囊菌不同发育阶段的表达量变化,应用实时荧光定量PCR技术对该菌的营养...冠突散囊菌(Eurotium cristatum)闭囊壳的产生和数量受各种与有性产孢相关的基因控制,而MAT基因(Mating type gene,MAT)是其中的关键基因之一,为调查MAT基因在冠突散囊菌不同发育阶段的表达量变化,应用实时荧光定量PCR技术对该菌的营养生长时期、无性产孢时期和有性产孢时期3个阶段的MAT基因表达量进行检测。结果显示:以营养生长时期为对照,在有性产孢时期MAT1-1-1基因上调31.12倍,MAT1-2-1基因上调5.87倍;在无性产孢时期MAT1-1-1基因上调4.25倍,MAT1-2-1基因仅为对照的0.03倍。表明,MAT基因与冠突散囊菌的有性产孢相关,其中MAT1-1-1基因还可能与无性产孢相关。展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFB3-401900)the National Natural Science Foundation of China(No.U21A20134)the Shandong Provincial Natural Science Foundation(Excellent Young Fund,No.ZR2022YQ48).
文摘The working environment of aerospace engines is extremely harsh with temperature exceeding 1700℃and accompanied by thermal coupling effects.In this condition,the materials employed in hypersonic aircraft undergo ablation issues,which can cause catastrophic accidents.Due to the excellent high-temperature stability and ablation resistance,HfC exhibits outstanding thermal expansion coefficient matching that of C/SiC composites.2.5D needle-punched C/SiC composites coated with HfC are prepared using a plasma spraying process,and a high-enthalpy arc-heated wind tunnel is employed to simulate the re-entry environment of aircraft at 8 Mach and an altitude of 32 km.The plasma-sprayed HfC-coated 2.5D needle-punched C/SiC composites are subjected to long-term dynamic testing,and their properties are investigated.Specifically,after the thermal assessment ablation experiment,the composite retains its overall structure and profile;the total mass ablation rate is 0.07445 g/s,the average linear ablation rate in the thickness direction is-0.0675μm/s,and the average linear ablation rate in the length direction is 13.907μm/s.Results verify that plasma-sprayed HfC coating exhibits excellent anti-oxidation and ablation resistance properties.Besides,the microstructure and ablation mechanism of the C/SiC composites are studied.It is believed that this work will offer guideline for the development of thermal protection materials and the assessment of structural thermal performance.
文摘The influence of the processing parameters on the properties of needle-punched composite geotextiles,compounded by polypropylene filament woven-fabrics and nonwoven fabrics is studied by using orthogonal design method. The relationship between tensile strength and peeling strength is discussed. The experimental results are offered as reference.
文摘A series of confined swell tests were conducted on a needle-punched geosynthetic clay liner (GCL) with tap water as the hydration medium. The effects of the static confining stress on the swelling characteristics of GCLs and the hydration time under different confining stresses were explored. Increasing the static confining stress led to: shorter hydration time; smaller final GCL height; less final GCL bulk void ratio; smaller final bentonite moisture content. The confined swell pressure determined for the tested GCL was 82.2 kPa, and the relationships between confining stress, final bulk void ratio (or final GCL height, final bentonite moisture content) were attained through the analyses of the confined swell test results in this study.
基金supported by the National Natural Science Foundation of China(32271379,82072396,52203309)Science and Technology Commission of Shanghai Municipality(23YF1421500,22YF1400400,21490711700)+4 种基金Cross Disciplinary Research Fund of Shanghai Ninth People's Hospital,Shanghai Jiao Tong University School of Medicine(JYJC202219)Shanghai's Top Priority Research Center(2022ZZ01017)CAMS Innovation Fund for Medical Sciences(CIFMS,2019-I2M-5-037)Fund of Department of Oral and Maxillofacial Surgery(Department 2022-04)the Fundamental Research Funds for the Central Universities(2232022D-09).
文摘Improving the osteogenic properties of bone grafts plays a critical role in the repair and functional restoration of critical-sized bone defects.The endogenous electric field,one of the most crucial physiological signals,has been confirmed to maintain physiological function and reconstruct the structure of bone,which is inadequate in bone defect sites.Strategies for the devel-opment of electroactive osteogenic biomaterials arise to remodel and promote the electrophysiological microenvironment.Among the electroactive materials,electret biomaterials can provide a stable and persistent endogenous electrical stimulation,which better conforms to the physiological microenvironment and has long-term effectiveness in the bone repair process.Herein,an electret hybrid electrospun fibrous mat(EHFM)was developed to mimic the structure of the natural extracellular matrix(ECM)with a suitable and persistent electrophysiological microenvironment.The EHFM was constructed with a core-shell structure,in which silicon dioxide electrets were loaded in the core-layer to remodel and maintain the electrical microenvironment over the long term.The EHFM significantly promoted the osteogenesis of bone mesenchymal stem cells(BMSCs)in vitro and showed remarkable ability in bone repair,which was three times better than that of the control group in a critical-sized rat calvarial defect model.Furthermore,it was verified that EHFM-derived osteogenesis was related to the activation of the calcium ion-sensing receptor(CaSR),while increasing intracellular calcium ion concentration of BMSCs.This study puts forward a novel engineering strategy to promote bone defect repair by remodeling a stable and persistent electrophysiological microenvironment,showing potential for clinical applications.
基金supported by the National Key Research and Development Program of China(2022YFB3804205)the National Natural Science Foundation of China(52203309,52373240)+3 种基金the Shanghai Sailing Program(22YF1400400)the Shanghai Rising-Star Program(23QA1400100)the Fundamental Research Funds for the Central Universities(2232022D-09)the Open Fund of State Key Laboratory of Biobased Fiber Manufacturing Technology(SKL202317).
文摘Developing an advanced individual protection cloth is a pivotal factor in combating global pathogen epidemics.However,formidable challenges are posed by the triangularity imbalance effect,necessitating the simultaneous fulfillment of require-ments for high comfort,high safety,and mass production.In this study,a mass-producible hybrid polytetrafluoroethylene nanofiber mat(HPNFM)was developed by integrating technologies of organic-inorganic hybridization and membrane asynchronous stretching.Exceptional comfort was attained by conferring waterproofing and breathability attributes,achieved through the radial island-chain architecture exhibiting hydrophobicity and nanoporosity.Furthermore,through the incorpo-ration of high-efficiency anti-pathogen nanoparticles,the HPNFM ensures high safety,demonstrating active antibacterial and antiviral effects.This is achieved through the synergistic effects of electrostatic induction and reactive oxygen species-based pathogen inactivation.More significantly,an HPNFM-based individual protective suit is designed and manufactured,which successfully encapsulates the advantages of high comfort,safety,and mass production,displaying competitiveness as a commercial product.Positioned as a viable strategy,this work holds substantial potential for practical applications in responding to future epidemics.
文摘A stable surface to move manpower and equipment is a key for the construction operations. To create a stable road surface, the road construction techniques are time-consuming and expensive for a traditional construction which requires compaction of soil, aggregate base, sub-base and asphaltic layers. A Geosynthetic Access Mat (GAM) system can serve as an alternative to other traditional construction techniques to accommodate temporary construction. Due to its rigidity, the mat system can provide substantial vertical resistance to the applied load under a large deflection subject to soil conditions. This paper provides details of GAM specifications, soil conditions, applications, installation procedure, comparison with other soil stabilization methods and Aramco experience for deployments of these mats.
文摘冠突散囊菌(Eurotium cristatum)闭囊壳的产生和数量受各种与有性产孢相关的基因控制,而MAT基因(Mating type gene,MAT)是其中的关键基因之一,为调查MAT基因在冠突散囊菌不同发育阶段的表达量变化,应用实时荧光定量PCR技术对该菌的营养生长时期、无性产孢时期和有性产孢时期3个阶段的MAT基因表达量进行检测。结果显示:以营养生长时期为对照,在有性产孢时期MAT1-1-1基因上调31.12倍,MAT1-2-1基因上调5.87倍;在无性产孢时期MAT1-1-1基因上调4.25倍,MAT1-2-1基因仅为对照的0.03倍。表明,MAT基因与冠突散囊菌的有性产孢相关,其中MAT1-1-1基因还可能与无性产孢相关。
