In the metallic components fabricated by the emerging selective laser melting(SLM)technology,most strategies used for strengthening the materials sacrifice the ductility,leading to the so-called strengthductility trad...In the metallic components fabricated by the emerging selective laser melting(SLM)technology,most strategies used for strengthening the materials sacrifice the ductility,leading to the so-called strengthductility trade-off.In the present study,we report that the strength and ductility of materials can be enhanced simultaneously by introducing nanoparticles,which can break the trade-off of the metallic materials.In the case of in-situ nano-TiB_(2)decorated AlSi10Mg composites,the introduced nanoparticles lead to columnar-to-equiaxed transition,grain refinement and texture elimination.With increasing content of nanoparticles,the strength increases continually.Significantly,the ductility first increases and then decreases.Our results show that the ductility is controlled by the competition between the crack-induced catastrophic fracture and ductile fracture associated with dislocation activities.The first increase of ductility is mainly attributed to the suppression of crack-induced catastrophic fracture when TiB_(2)nanoparticles present.With the further increase of TiB_(2)nanoparticles,the subsequent decrease of ductility is mainly controlled by dislocation activities.Thus,the materials will exhibit the optimum strength and ductility combination in a certain range of TiB_(2)nanoparticles.This study clarifies the physical mechanism controlling ductility for nano-TiB_(2)decorated Al Si10Mg composites,which provides the insights for the design of structural materials.展开更多
This paper details an investigation of the effects of oxide stringers on theβ-phase depletion behaviour in thermally sprayed CoNiCrAlY coatings.Vacuum Plasma Sprayed(VPS)Co NiCrAlY coatings,which are free of oxide st...This paper details an investigation of the effects of oxide stringers on theβ-phase depletion behaviour in thermally sprayed CoNiCrAlY coatings.Vacuum Plasma Sprayed(VPS)Co NiCrAlY coatings,which are free of oxide stringers,are used as the reference materials in comparison with High-Velocity Oxy-Fuel(HVOF)sprayed CoNiCrAlY coatings during isothermal oxidation at 1100℃.An outer layer of spinel oxides and an inner layer of alumina are formed in the as-sprayed coatings,while only a single alumina scale is found in the heat-treated coatings.Lessβ-phase depletion occurred in the HVOF coatings than in the VPS coatings.It was found that theβphases tend to coalesce at the oxide stringers in the HVOF coatings,which is likely due to the internal oxide particles and stringers acting as short diffusion barriers to tie up theβphase and inhibit theβ-phase depletion.展开更多
Reports on corrosion failure of cable bolts,used in mining and civil industries,have been increasing in the past two decades.The previous studies found that pitting corrosion on the surface of a cable bolt can initiat...Reports on corrosion failure of cable bolts,used in mining and civil industries,have been increasing in the past two decades.The previous studies found that pitting corrosion on the surface of a cable bolt can initiate premature failure of the bolt.In this study,the role of Acidithiobacillus ferrooxidans(A.ferrooxidans)bacterium in the occurrence of pitting corrosion in cable bolts was studied.Stressed coupons,made from the wires of cable bolts,were immersed in testing bottles containing groundwater collected from an underground coal mine and a mixture of A.ferrooxidans and geomaterials.It was observed that A.ferrooxidans caused pitting corrosion on the surface of cable bolts in the near-neutral environment.The presence of geomaterials slightly affected the p H of the environment;however,it did not have any significant influence on the corrosion activity of A.ferrooxidans.This study suggests that the common bacterium A.ferrooxidans found in many underground environments can be a threat to cable bolts'integrity by creating initiation points for other catastrophic failures such as stress corrosion cracking.展开更多
Press-hardened steel(PHS)with an ultimate tensile strength(UTS)of 1500 MPa has been widely used in automotive body-in-white in the last two decades,due to its ultra-high strength and excellent formability that is achi...Press-hardened steel(PHS)with an ultimate tensile strength(UTS)of 1500 MPa has been widely used in automotive body-in-white in the last two decades,due to its ultra-high strength and excellent formability that is achieved by hot stamping process.However,the application of PHS with UTS exceeding 1500 MPa in automotive industry could be deferred due to the increased risk of hydrogen embrittlement.To reduce this kind of risk,recent research efforts have been focused on various ways to optimize the microstructure of PHS.The present review intends to summarize these efforts,to highlight present solutions to address hydrogen embrittlement,and to shed light on directions for future improvement.The influence of microstructure on the hydrogen embrittlement of PHS has been discussed in terms of both the steel substrate and the surface condition.The substrate part covers the influence of martensite,carbides,inclusions,and retained austenite,while the surface part covers decarburization and oxidation,pre-coating,and trimming.展开更多
The assistance of alloying elements provides enormous opportunities for the discovery of high-performance face-centered cubic(FCC)medium-entropy alloys(MEAs).In this work,the influence of al-loying element Mo on the p...The assistance of alloying elements provides enormous opportunities for the discovery of high-performance face-centered cubic(FCC)medium-entropy alloys(MEAs).In this work,the influence of al-loying element Mo on the phase stability,stacking fault energy(SFE),deformation mechanisms,lattice distortion,and mechanical properties of(CoCrNi)100-x Mox(0≤x≤10)MEAs was synthetically explored with the first-principles calculations.It indicates that the FCC phase remains metastable at 0 K,and its stability degenerates with increasing Mo content.The monotonous decrease of SFE is revealed with the rise of Mo content,which promotes the activation of stacking faults,deformation twinning,or martensitic transformation.Raising Mo content also causes the aggravation of lattice distortion and thus triggers in-tense solid solution strengthening.Significantly,the essential criterion for the composition design of FCC(CoCrNi)100-x Mo MEAs with superior strength-ductility combination was established based on the syner-gistic effects between multiple deformation mechanisms and solid solution strengthening.According to the criterion,the optimal composition is predetermined as(CoCrNi)93 Mo7 MEA.The criterion is proved to be effective,and it can provide valuable inspiration for the development of alloying-element reinforced FCC multi-principal element alloys.展开更多
It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation mo...It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.展开更多
The phase constitutes and phase compositions in the eight alloys designed with dif-ferent compositions of Al--Zn--Cu system have been determined after the homogenous treatment and then equilibrium cooling to 20℃by us...The phase constitutes and phase compositions in the eight alloys designed with dif-ferent compositions of Al--Zn--Cu system have been determined after the homogenous treatment and then equilibrium cooling to 20℃by use of optical microscope,electron probe microanalysis and X--ray diffraction.It has been found that there existed the T'phase in the seven alloys.Consequently,it was testified that the T'phase was stable at room temperature.At the same time,the phase relationship was not locally right for the isothermal section of 20℃of Al--Zn--Cu system of the ASM published in 1997.展开更多
Several nc-TiN/a-TiB2 thin films comprised of nanocrystalline (nc-) TiN and amor phous (a-) TiB2 phases were deposited on Si(100) at room temperature by reactive unbalanced dc magnetron sputtering, followed by vacuum ...Several nc-TiN/a-TiB2 thin films comprised of nanocrystalline (nc-) TiN and amor phous (a-) TiB2 phases were deposited on Si(100) at room temperature by reactive unbalanced dc magnetron sputtering, followed by vacuum annealed at 400, 600, 80 0 and 1000℃ for 1h, respectively. Effects of B content on microstructure, mecha nical behaviors and thermal microstructure stability have been investigated by X -ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and nanoindentation measurements. The results indicated that B addition greatly affected both microstructure and mechanical behavior of nc-Ti N/a-TiB2 thin films. With increasing B content the grain size decreased. A maxim um hardness value of about 33GPa was obtained at B content of about 19at.%. The improved mechanical properties of nc-TiN/a-TiB2 films with the addition of B int o TiN were attributed to their densified microstructure with development of fine grain size. Only addition of sufficient B could restrain grain growth during an nealing. High B content resulted in high microstructure stability. The crystalli zation of amorphous matrix occurred at about 800℃, forming TiB or TiB2 crystall ite, depending on B content. Before that no change in bonding configuration was found.展开更多
Friction and sliding wear behaviour of Ti-B-N coatings against AISI440C steel ba ll and WC-6wt%Co ball were studied by using pin-on-disk tribometer along with mi crostructure characterization using optical microscopy ...Friction and sliding wear behaviour of Ti-B-N coatings against AISI440C steel ba ll and WC-6wt%Co ball were studied by using pin-on-disk tribometer along with mi crostructure characterization using optical microscopy (OM), scanning electron m icroscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is shown that the wear resistance of film depended on the wear mechanism. In the case of AISI440C steel, adhesive wear were pre-dominant and the wear rate increased sharply to a maximum when N content reach ~38at.%. This might be related to the change of fi lm microstructure and phase configuration, so the least adhesive transfer of tri bo-film was observed. If WC-6wt%Co ball was used, less deformation wear debris w as observed, this was responsible for the rise of wear rate. Despite of differen t wear modes, friction coefficients in both cases were found to depend mainly on the formation and the amount of h-BN phase. Elemental analysis by energy disper sive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) revealed that oxygen participated in the wear behavior by reacting with films to form the deb ris comprised of various types of Ti oxide including TiO, TiO2 and Ti2O3 , which increased wear resistance.展开更多
yThe EIS on theanodic process of pure Zn in an alkaline solution wereperformed and fitted using the expression of Faradic admittance,based on which the mechanism of the process was propose...yThe EIS on theanodic process of pure Zn in an alkaline solution wereperformed and fitted using the expression of Faradic admittance,based on which the mechanism of the process was proposed.The results showed that besides electrode potential E the electrochemical reaction rate was affected by the adsorption of Zn(OH)ads on the electrode surface and the diffusion of in the electrolyte in active region,and only by the covering of passivation layer on the electrode surface in both transitive and passivation regions.The equivalent circuit sapplied in these various circumstances were proposed and the variation of some parameters and state variables was also discussed.展开更多
Shape morphing is a critical aptitude for the survival of organisms and is determined by anisotropic tissue composition and directional orientation of micro-and nanostructures within cell walls,resulting in diferent s...Shape morphing is a critical aptitude for the survival of organisms and is determined by anisotropic tissue composition and directional orientation of micro-and nanostructures within cell walls,resulting in diferent swelling behaviors.Recent eforts have been dedicated to mimicking the behaviors that nature has perfected over billions of years.We present a robust strategy for preparing 3D periodically patterned single-component sodium alginate hydrogel sheets cross-linked with Ca^(2+)ions,which can reversibly deform and be retained into various desirable inside-out shapes as triggered by biocompatible ions(Na^(+)/Ca^(2+)).By changing the orientations of the patterned microchannels or triggering with Na^(+)/Ca^(2+)ions,various 3D twisting,tubular,and plantinspired architectures can be facilely programmed.Not only can the transformation recover their initial shapes reversibly,but also it can keep the designated shapes without continuous stimuli.Tese inside-out 3D reversible ion-triggered hydrogel transformations shall inspire more attractive applications in tissue engineering,biomedical devices,and sof robotics felds.展开更多
The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of...The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.展开更多
Background High-voltage CMOS is a promising technology for the pixel sensor of tracking detectors in the collider experiments.Extensive studies are being carried out by theATLASCollaboration to investigate the possibi...Background High-voltage CMOS is a promising technology for the pixel sensor of tracking detectors in the collider experiments.Extensive studies are being carried out by theATLASCollaboration to investigate the possibility of using theHV-CMOS technology in the HL-LHC upgrade of the ATLAS inner tracker detector.Purpose The CaRIBOu(Control and Readout Itk BOards)is a modular test system developed to test the HV-CMOS pixel sensor prototypes and demonstrators.Methods This test system consists of pixel sensor specific front-end chip boards,a control and readout board(CaR board),a central interface board and the back-end DAQ system.Currently,two DAQ solutions are available for the CaRIBOu system,one is based on the FELIX(front-end link eXchange)readout system and the other is based on the Gigabit Ethernet link.Results Various testbeam experiments have been carried out with the CaRIBOu system since 2015 for the pixel sensors fabricated by the AMS HV-CMOS 180 nm and 350 nm technologies.Conclusion The test results show that this test system is very flexible and could be adapted to the test of different pixel sensors with minimum effort,and the performance meets the testbeam requirements.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2018YFB1106302)。
文摘In the metallic components fabricated by the emerging selective laser melting(SLM)technology,most strategies used for strengthening the materials sacrifice the ductility,leading to the so-called strengthductility trade-off.In the present study,we report that the strength and ductility of materials can be enhanced simultaneously by introducing nanoparticles,which can break the trade-off of the metallic materials.In the case of in-situ nano-TiB_(2)decorated AlSi10Mg composites,the introduced nanoparticles lead to columnar-to-equiaxed transition,grain refinement and texture elimination.With increasing content of nanoparticles,the strength increases continually.Significantly,the ductility first increases and then decreases.Our results show that the ductility is controlled by the competition between the crack-induced catastrophic fracture and ductile fracture associated with dislocation activities.The first increase of ductility is mainly attributed to the suppression of crack-induced catastrophic fracture when TiB_(2)nanoparticles present.With the further increase of TiB_(2)nanoparticles,the subsequent decrease of ductility is mainly controlled by dislocation activities.Thus,the materials will exhibit the optimum strength and ductility combination in a certain range of TiB_(2)nanoparticles.This study clarifies the physical mechanism controlling ductility for nano-TiB_(2)decorated Al Si10Mg composites,which provides the insights for the design of structural materials.
基金supported by Zhejiang Provincial Natural Science Foundation under Grant No.LQ18E010002Natural Science Foundation of China under Grant No.51901107+1 种基金Ningbo Natural Science Foundation under Grant No.2018A610168,2019A610176Zhejiang Qianjiang Talent Scheme under Grant No.QJD1803012。
文摘This paper details an investigation of the effects of oxide stringers on theβ-phase depletion behaviour in thermally sprayed CoNiCrAlY coatings.Vacuum Plasma Sprayed(VPS)Co NiCrAlY coatings,which are free of oxide stringers,are used as the reference materials in comparison with High-Velocity Oxy-Fuel(HVOF)sprayed CoNiCrAlY coatings during isothermal oxidation at 1100℃.An outer layer of spinel oxides and an inner layer of alumina are formed in the as-sprayed coatings,while only a single alumina scale is found in the heat-treated coatings.Lessβ-phase depletion occurred in the HVOF coatings than in the VPS coatings.It was found that theβphases tend to coalesce at the oxide stringers in the HVOF coatings,which is likely due to the internal oxide particles and stringers acting as short diffusion barriers to tie up theβphase and inhibit theβ-phase depletion.
基金funding provided by the Australian Research Council(ARC)Linkage Projects(Nos.100200238 and 140100153)supported by Jennmar Australia Pty Ltd+5 种基金Glencore Australia Holdings Pty LtdIllawarra Coal Holdings Pty LtdSpringvale Coal Pty LtdAnglo Operations Pty LtdAnglo Coal AustraliaNarrabri Coal Operations Pty Ltd。
文摘Reports on corrosion failure of cable bolts,used in mining and civil industries,have been increasing in the past two decades.The previous studies found that pitting corrosion on the surface of a cable bolt can initiate premature failure of the bolt.In this study,the role of Acidithiobacillus ferrooxidans(A.ferrooxidans)bacterium in the occurrence of pitting corrosion in cable bolts was studied.Stressed coupons,made from the wires of cable bolts,were immersed in testing bottles containing groundwater collected from an underground coal mine and a mixture of A.ferrooxidans and geomaterials.It was observed that A.ferrooxidans caused pitting corrosion on the surface of cable bolts in the near-neutral environment.The presence of geomaterials slightly affected the p H of the environment;however,it did not have any significant influence on the corrosion activity of A.ferrooxidans.This study suggests that the common bacterium A.ferrooxidans found in many underground environments can be a threat to cable bolts'integrity by creating initiation points for other catastrophic failures such as stress corrosion cracking.
基金M.X.Huang acknowledges the support from Guangzhou Municipal Science and Technology Project(No.202007020007)Guangdong Basic and Applied Basic Research Foundation of China(No.2020B1515130007).
文摘Press-hardened steel(PHS)with an ultimate tensile strength(UTS)of 1500 MPa has been widely used in automotive body-in-white in the last two decades,due to its ultra-high strength and excellent formability that is achieved by hot stamping process.However,the application of PHS with UTS exceeding 1500 MPa in automotive industry could be deferred due to the increased risk of hydrogen embrittlement.To reduce this kind of risk,recent research efforts have been focused on various ways to optimize the microstructure of PHS.The present review intends to summarize these efforts,to highlight present solutions to address hydrogen embrittlement,and to shed light on directions for future improvement.The influence of microstructure on the hydrogen embrittlement of PHS has been discussed in terms of both the steel substrate and the surface condition.The substrate part covers the influence of martensite,carbides,inclusions,and retained austenite,while the surface part covers decarburization and oxidation,pre-coating,and trimming.
基金the funding support for the work by the National Natural Science Foundation of China(NSFC)under Grant No.52071316the Youth Project of Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202300755)+1 种基金the Natural Science Foundation of Chongqing(Grant No.cstc2021jcyj-msxmX0697)the Project of Science Foundation in Chongqing Jiaotong University(Grant No.F1210023).
文摘The assistance of alloying elements provides enormous opportunities for the discovery of high-performance face-centered cubic(FCC)medium-entropy alloys(MEAs).In this work,the influence of al-loying element Mo on the phase stability,stacking fault energy(SFE),deformation mechanisms,lattice distortion,and mechanical properties of(CoCrNi)100-x Mox(0≤x≤10)MEAs was synthetically explored with the first-principles calculations.It indicates that the FCC phase remains metastable at 0 K,and its stability degenerates with increasing Mo content.The monotonous decrease of SFE is revealed with the rise of Mo content,which promotes the activation of stacking faults,deformation twinning,or martensitic transformation.Raising Mo content also causes the aggravation of lattice distortion and thus triggers in-tense solid solution strengthening.Significantly,the essential criterion for the composition design of FCC(CoCrNi)100-x Mo MEAs with superior strength-ductility combination was established based on the syner-gistic effects between multiple deformation mechanisms and solid solution strengthening.According to the criterion,the optimal composition is predetermined as(CoCrNi)93 Mo7 MEA.The criterion is proved to be effective,and it can provide valuable inspiration for the development of alloying-element reinforced FCC multi-principal element alloys.
基金funding from the Australian Research Council(ARC) via DP180103205。
文摘It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.
基金This work was supported by National Natural Science Foundation of China(No.50171019)
文摘The phase constitutes and phase compositions in the eight alloys designed with dif-ferent compositions of Al--Zn--Cu system have been determined after the homogenous treatment and then equilibrium cooling to 20℃by use of optical microscope,electron probe microanalysis and X--ray diffraction.It has been found that there existed the T'phase in the seven alloys.Consequently,it was testified that the T'phase was stable at room temperature.At the same time,the phase relationship was not locally right for the isothermal section of 20℃of Al--Zn--Cu system of the ASM published in 1997.
文摘Several nc-TiN/a-TiB2 thin films comprised of nanocrystalline (nc-) TiN and amor phous (a-) TiB2 phases were deposited on Si(100) at room temperature by reactive unbalanced dc magnetron sputtering, followed by vacuum annealed at 400, 600, 80 0 and 1000℃ for 1h, respectively. Effects of B content on microstructure, mecha nical behaviors and thermal microstructure stability have been investigated by X -ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and nanoindentation measurements. The results indicated that B addition greatly affected both microstructure and mechanical behavior of nc-Ti N/a-TiB2 thin films. With increasing B content the grain size decreased. A maxim um hardness value of about 33GPa was obtained at B content of about 19at.%. The improved mechanical properties of nc-TiN/a-TiB2 films with the addition of B int o TiN were attributed to their densified microstructure with development of fine grain size. Only addition of sufficient B could restrain grain growth during an nealing. High B content resulted in high microstructure stability. The crystalli zation of amorphous matrix occurred at about 800℃, forming TiB or TiB2 crystall ite, depending on B content. Before that no change in bonding configuration was found.
文摘Friction and sliding wear behaviour of Ti-B-N coatings against AISI440C steel ba ll and WC-6wt%Co ball were studied by using pin-on-disk tribometer along with mi crostructure characterization using optical microscopy (OM), scanning electron m icroscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is shown that the wear resistance of film depended on the wear mechanism. In the case of AISI440C steel, adhesive wear were pre-dominant and the wear rate increased sharply to a maximum when N content reach ~38at.%. This might be related to the change of fi lm microstructure and phase configuration, so the least adhesive transfer of tri bo-film was observed. If WC-6wt%Co ball was used, less deformation wear debris w as observed, this was responsible for the rise of wear rate. Despite of differen t wear modes, friction coefficients in both cases were found to depend mainly on the formation and the amount of h-BN phase. Elemental analysis by energy disper sive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) revealed that oxygen participated in the wear behavior by reacting with films to form the deb ris comprised of various types of Ti oxide including TiO, TiO2 and Ti2O3 , which increased wear resistance.
文摘yThe EIS on theanodic process of pure Zn in an alkaline solution wereperformed and fitted using the expression of Faradic admittance,based on which the mechanism of the process was proposed.The results showed that besides electrode potential E the electrochemical reaction rate was affected by the adsorption of Zn(OH)ads on the electrode surface and the diffusion of in the electrolyte in active region,and only by the covering of passivation layer on the electrode surface in both transitive and passivation regions.The equivalent circuit sapplied in these various circumstances were proposed and the variation of some parameters and state variables was also discussed.
基金We are indebted to Dr.Massimiliano Galluzzi for performing AFM analysis of the samples.This work was supported by the National Key R&D Program of China(2017YFA0701303,2016YFA0201001)National Natural Science Foundation of China(21404116)+3 种基金the Youth Innovation Promotion Association of CAS,CAS Key Laboratory of Health Informatics,Shenzhen Institutes of Advanced Technology,Special Support Project for Outstanding Young Scholars of Guangdong Province(2015TQ01R292)Guangdong-Hong Kong Technology Cooperation Funding(2017A050506040)Shenzhen Science and Technology Innovation Committee(JCYJ20150316144521974,JCYJ20170818161757684,JCYJ2017-0413152640731)Shenzhen Peacock Plan.
文摘Shape morphing is a critical aptitude for the survival of organisms and is determined by anisotropic tissue composition and directional orientation of micro-and nanostructures within cell walls,resulting in diferent swelling behaviors.Recent eforts have been dedicated to mimicking the behaviors that nature has perfected over billions of years.We present a robust strategy for preparing 3D periodically patterned single-component sodium alginate hydrogel sheets cross-linked with Ca^(2+)ions,which can reversibly deform and be retained into various desirable inside-out shapes as triggered by biocompatible ions(Na^(+)/Ca^(2+)).By changing the orientations of the patterned microchannels or triggering with Na^(+)/Ca^(2+)ions,various 3D twisting,tubular,and plantinspired architectures can be facilely programmed.Not only can the transformation recover their initial shapes reversibly,but also it can keep the designated shapes without continuous stimuli.Tese inside-out 3D reversible ion-triggered hydrogel transformations shall inspire more attractive applications in tissue engineering,biomedical devices,and sof robotics felds.
基金supported by the National Key R&D Program of China under Contract No.2022YFA1602200the International Partnership Program of the Chineses Academy of Sciences under Grant No.211134KYSB20200057the STCF Key Technology Research and Development Project.
文摘The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.
文摘Background High-voltage CMOS is a promising technology for the pixel sensor of tracking detectors in the collider experiments.Extensive studies are being carried out by theATLASCollaboration to investigate the possibility of using theHV-CMOS technology in the HL-LHC upgrade of the ATLAS inner tracker detector.Purpose The CaRIBOu(Control and Readout Itk BOards)is a modular test system developed to test the HV-CMOS pixel sensor prototypes and demonstrators.Methods This test system consists of pixel sensor specific front-end chip boards,a control and readout board(CaR board),a central interface board and the back-end DAQ system.Currently,two DAQ solutions are available for the CaRIBOu system,one is based on the FELIX(front-end link eXchange)readout system and the other is based on the Gigabit Ethernet link.Results Various testbeam experiments have been carried out with the CaRIBOu system since 2015 for the pixel sensors fabricated by the AMS HV-CMOS 180 nm and 350 nm technologies.Conclusion The test results show that this test system is very flexible and could be adapted to the test of different pixel sensors with minimum effort,and the performance meets the testbeam requirements.
