The Vacuum diffusion bonding between nickel-base superalloy K24 and heatresisting steel 1Cr11Ni2W2MoV was studied and the effects of welding parameters,including bonding temperature T,pressure P,time t,vacuum V and in...The Vacuum diffusion bonding between nickel-base superalloy K24 and heatresisting steel 1Cr11Ni2W2MoV was studied and the effects of welding parameters,including bonding temperature T,pressure P,time t,vacuum V and interlayer thickness h ,on the microstructure and properties of the joint were investigated.The optimum parameters for the diffusion bonding were found to be:T=1100￣1200℃,t=5￣30 MPa,V≥1×10-2 Pa.When the welded specimens are tensioned at room temperature,ductile fracture takes place at the nickel-base superalloy part or at the joint and the tensile strength reaches 850 MPa,When the tensile tests are carried out at 500℃ ,all the bonded specimens fractured at heat-resisting steel part,and tensile strength is 750 MPa.The interlayer thickness greatly affects the joint properties,and the interlayer thickness depends on the size of the bonded specimen.The impeller of nickel-base superalloy K24 and shaft of heat-resisting steel 1Cr11Ni2MoV,which are used in aerospace engine,has been successfully jointed jointed by means of high frequency induction diffusion bonding.展开更多
Given its intriguing band structure and unique tunable bandgap,AB-stacked bilayer graphene has great potentials in the applications of high-end electronics,optoelectronics and semiconductors.The epitaxial growth of AB...Given its intriguing band structure and unique tunable bandgap,AB-stacked bilayer graphene has great potentials in the applications of high-end electronics,optoelectronics and semiconductors.The epitaxial growth of AB-stacked single-crystal bilayer graphene films requires a strict AB-stacked lattice,identical orientations and seamless stitching of bilayer graphene islands.However,the particles inevitably present on the metal surface that produced during high temperature growth would induce random orientations,twisted stacking islands,and uncontrollable multilayers,which is a great challenge to overcome.Here,we propose a heat-resisting-box assisted strategy to produce nearly pure AB-stacked bilayer graphene single-crystal films on Cu/Ni(111)foils.With our technique,the particles on the Cu/Ni(111)surface are effectively eliminated,which greatly minimizes the occurrence of randomly twisted islands and uncontrollable multilayers.The as-grown AB-stacked bilayer graphene films show>99%alignment and>99%AB stacking order.Our work provides a promising method towards the growth of pure AB-stacked bilayer graphene single crystals and would accelerate its device applications.展开更多
Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging work.Herein,a simple donor-acceptor(D-A)molecule,9-(1H...Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging work.Herein,a simple donor-acceptor(D-A)molecule,9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole(CzBtrz),was investigated.This simple molecule not only exhibits multiple emissions including white light,thermally activated delayed fluorescence(TADF)and ultralong RTP with a lifetime of 988.54 ms at 545 nm,but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K(ΔT=273 K),exceeding those of other RTP systems.Meanwhile,this molecule shows the time-evolved dynamic RTP.The experimental and theoretical an-alyses from CzBtrz crystal demonstrate that the intramolecular charge transfer(ICT)interaction and molecular stacking play an important role in the generation of RTP.Therefore,this work provides an efficient strategy to design ultrahigh heat-resistant RTP,ultralong RTP and single-phased white-light emitting materials.展开更多
A new complex,Co（0.5）Ni（0.5）（C2H6N2O）6SO4（Ⅰ）, was synthesized and its single crystal was obtained from aqueous solution by evaporating solvent slowly. Single-crystal X-ray analysis revealed that the complex b...A new complex,Co（0.5）Ni（0.5）（C2H6N2O）6SO4（Ⅰ）, was synthesized and its single crystal was obtained from aqueous solution by evaporating solvent slowly. Single-crystal X-ray analysis revealed that the complex belongs to trigonal system, space group R-3c, with a = b = 10.999（2） A, c = 40.439（13） A, V = 4237（2）A3, Z = 6, Dc = 1.410 g/cm3, Mr = 599.41, μ = 0.785 mm-1, F（000） = 1893, the final R = 0.0330 and wR = 0.0926（I 〉 2σ（I））. IR spectrum and compositional analyses（elemental analyzer and ICP） were used to characterize the composition of the product. TGA（Thermal Gravimetric Analysis） showed that complex Ⅰ remained stable until it is heated up to 200 ℃, indicating its good thermostability. The main transmission peak of complex Ⅰ in UV-Vis spectrum appeared at 290 nm, making it an eligible material for ultraviolet light filters（ULF）.展开更多
文摘The Vacuum diffusion bonding between nickel-base superalloy K24 and heatresisting steel 1Cr11Ni2W2MoV was studied and the effects of welding parameters,including bonding temperature T,pressure P,time t,vacuum V and interlayer thickness h ,on the microstructure and properties of the joint were investigated.The optimum parameters for the diffusion bonding were found to be:T=1100￣1200℃,t=5￣30 MPa,V≥1×10-2 Pa.When the welded specimens are tensioned at room temperature,ductile fracture takes place at the nickel-base superalloy part or at the joint and the tensile strength reaches 850 MPa,When the tensile tests are carried out at 500℃ ,all the bonded specimens fractured at heat-resisting steel part,and tensile strength is 750 MPa.The interlayer thickness greatly affects the joint properties,and the interlayer thickness depends on the size of the bonded specimen.The impeller of nickel-base superalloy K24 and shaft of heat-resisting steel 1Cr11Ni2MoV,which are used in aerospace engine,has been successfully jointed jointed by means of high frequency induction diffusion bonding.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2020B1515020043,2023A1515012743)Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030002)+4 种基金the National Natural Science Foundation of China(Nos.12322406,52102043,61905215,52025023,51991342,52021006)the Key R&D Program of Guangdong Province(No.2020B010189001)the National Key R&D Program of China(No.2022YFA1403500)the Pearl River Talent Recruitment Program of Guangdong Province(No.2019ZT08C321)the Key Project of Science and Technology of Guangzhou(No.202201010383).
文摘Given its intriguing band structure and unique tunable bandgap,AB-stacked bilayer graphene has great potentials in the applications of high-end electronics,optoelectronics and semiconductors.The epitaxial growth of AB-stacked single-crystal bilayer graphene films requires a strict AB-stacked lattice,identical orientations and seamless stitching of bilayer graphene islands.However,the particles inevitably present on the metal surface that produced during high temperature growth would induce random orientations,twisted stacking islands,and uncontrollable multilayers,which is a great challenge to overcome.Here,we propose a heat-resisting-box assisted strategy to produce nearly pure AB-stacked bilayer graphene single-crystal films on Cu/Ni(111)foils.With our technique,the particles on the Cu/Ni(111)surface are effectively eliminated,which greatly minimizes the occurrence of randomly twisted islands and uncontrollable multilayers.The as-grown AB-stacked bilayer graphene films show>99%alignment and>99%AB stacking order.Our work provides a promising method towards the growth of pure AB-stacked bilayer graphene single crystals and would accelerate its device applications.
基金supported by the National Natural Science Foundation of China(U1904183,22171123 and 22102068)the Natural Science Foundation for Excellent Young Scholars of Henan Province(232300421083,212300410061)+2 种基金the Program for Innovative Research Team from the University of Henan Province(24IRTSTHN005)the Science and Technology R&D program of the Joint Funds of Henan Province(225200810082)the Open Foundation of State Key Laboratory of Structural Chemistry(20230021).
文摘Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging work.Herein,a simple donor-acceptor(D-A)molecule,9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole(CzBtrz),was investigated.This simple molecule not only exhibits multiple emissions including white light,thermally activated delayed fluorescence(TADF)and ultralong RTP with a lifetime of 988.54 ms at 545 nm,but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K(ΔT=273 K),exceeding those of other RTP systems.Meanwhile,this molecule shows the time-evolved dynamic RTP.The experimental and theoretical an-alyses from CzBtrz crystal demonstrate that the intramolecular charge transfer(ICT)interaction and molecular stacking play an important role in the generation of RTP.Therefore,this work provides an efficient strategy to design ultrahigh heat-resistant RTP,ultralong RTP and single-phased white-light emitting materials.
基金Supported by Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences
文摘A new complex,Co（0.5）Ni（0.5）（C2H6N2O）6SO4（Ⅰ）, was synthesized and its single crystal was obtained from aqueous solution by evaporating solvent slowly. Single-crystal X-ray analysis revealed that the complex belongs to trigonal system, space group R-3c, with a = b = 10.999（2） A, c = 40.439（13） A, V = 4237（2）A3, Z = 6, Dc = 1.410 g/cm3, Mr = 599.41, μ = 0.785 mm-1, F（000） = 1893, the final R = 0.0330 and wR = 0.0926（I 〉 2σ（I））. IR spectrum and compositional analyses（elemental analyzer and ICP） were used to characterize the composition of the product. TGA（Thermal Gravimetric Analysis） showed that complex Ⅰ remained stable until it is heated up to 200 ℃, indicating its good thermostability. The main transmission peak of complex Ⅰ in UV-Vis spectrum appeared at 290 nm, making it an eligible material for ultraviolet light filters（ULF）.
