Fe-N thin films were fabricated on both 100Si and NaCl substrates by RF magnetron sputtering under low nitrogen partial pressure.The microstructure and magnetic properties of Fe-N thin films were investigated with the...Fe-N thin films were fabricated on both 100Si and NaCl substrates by RF magnetron sputtering under low nitrogen partial pressure.The microstructure and magnetic properties of Fe-N thin films were investigated with the increase of the substrate temperature(Ts)and the annealing temperature(Ta).It is more difficult for nitrogen atoms to enter the Fe lattice under higher Ts above 150℃.The phase evolution is visible at higher Ta above 200℃.The phase transformation ofα''-Fe16N2 occurred at 400℃.The change of crystal size with Ta was clearly visible from bright and dark field images.The clear high-resolution electron microscope(HREM)images of 110α,111γ',112α'',and 200α''phases were observed.The interplanar distances from TEM(transmission electron microscope)and HREM match the calculated values very well.From the results of the vibrating sample magnetometer(VSM),the good magnetic properties of Fe-N films were obtained at 150℃of Ts and 200℃of Ta,respectively.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
The surface modification of multi-walled carbon nanotubes(MWCNTs) was carried out using plasma treatment. The microstructures of the prepared cermets with different additions of MWCNTs were investigated by scanning el...The surface modification of multi-walled carbon nanotubes(MWCNTs) was carried out using plasma treatment. The microstructures of the prepared cermets with different additions of MWCNTs were investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive X-ray analysis(EDX), and X-ray diffraction(XRD). Mechanical properties such as transverse rupture strength(TRS), fracture toughness(K_(IC)), and hardness(HRA) were measured. The results showed that some reactive groups were successfully modified on the surface of MWCNTs, resulting in the improvement of dispersibility. Most of the amorphous carbons and impurities were peeled from the MWCNTs. Increasing MWCNT addition decreased the dissolution of tungsten, titanium, and molybdenum in the binder phase. The cermet with 0.5 wt% MWCNT addition showed the highest TRS and fracture toughness. The strengthening mechanisms were attributed to the finer grain size, the homogeneous microstructure, and the higher volume fraction of binder phase in the binder. The toughening mechanisms were characterized by bridging and pulling-out.展开更多
基金supported by the National Natural Science Foundation of China(No.50674071)Tianjin Natural Science Foundation of China(No.06YFJZJC01300)+1 种基金the Program for New Century Excellent Talents in University(NCET-06-0245)the Platform Project of Tianjin for Innovation in Science and Technology and Environmental Construction(No.06TXTJJC13900).
文摘Fe-N thin films were fabricated on both 100Si and NaCl substrates by RF magnetron sputtering under low nitrogen partial pressure.The microstructure and magnetic properties of Fe-N thin films were investigated with the increase of the substrate temperature(Ts)and the annealing temperature(Ta).It is more difficult for nitrogen atoms to enter the Fe lattice under higher Ts above 150℃.The phase evolution is visible at higher Ta above 200℃.The phase transformation ofα''-Fe16N2 occurred at 400℃.The change of crystal size with Ta was clearly visible from bright and dark field images.The clear high-resolution electron microscope(HREM)images of 110α,111γ',112α'',and 200α''phases were observed.The interplanar distances from TEM(transmission electron microscope)and HREM match the calculated values very well.From the results of the vibrating sample magnetometer(VSM),the good magnetic properties of Fe-N films were obtained at 150℃of Ts and 200℃of Ta,respectively.
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.
基金financially supported by the Science and Technology Department of Fujian Province under Project No.2014H0037the Production,Education and Research of Fujian Provincial Education Department under Project No.JK2016040the Key Subject Project of Fujian Province
文摘The surface modification of multi-walled carbon nanotubes(MWCNTs) was carried out using plasma treatment. The microstructures of the prepared cermets with different additions of MWCNTs were investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive X-ray analysis(EDX), and X-ray diffraction(XRD). Mechanical properties such as transverse rupture strength(TRS), fracture toughness(K_(IC)), and hardness(HRA) were measured. The results showed that some reactive groups were successfully modified on the surface of MWCNTs, resulting in the improvement of dispersibility. Most of the amorphous carbons and impurities were peeled from the MWCNTs. Increasing MWCNT addition decreased the dissolution of tungsten, titanium, and molybdenum in the binder phase. The cermet with 0.5 wt% MWCNT addition showed the highest TRS and fracture toughness. The strengthening mechanisms were attributed to the finer grain size, the homogeneous microstructure, and the higher volume fraction of binder phase in the binder. The toughening mechanisms were characterized by bridging and pulling-out.
