TiNi shape memory alloy porosint, a promising artificial bone material, was prepared by self propagating high temperature synthesis method. It is found that the key technical parameter affecting the porosity, the sh...TiNi shape memory alloy porosint, a promising artificial bone material, was prepared by self propagating high temperature synthesis method. It is found that the key technical parameter affecting the porosity, the shape and distribution of the bores in the synthesized product is the pre heating temperature of green compact. While the pre heating temperature varies between 523 K and 673 K, the TiNi shape memory alloy porosint with wholly homogeneously distributing bores will be gained. The porosity of the porosint is 70% when the pre heating temperature is near 673 K, which is maximal under different pre heating temperatures. The compressive strength of TiNi SMA porosint with a porosity of 70% manufactured by SHS is up to 100 MPa and the percentage recovered is 92%.展开更多
By using the semi-relativistic distorted-wave Born exchange method,electron impact cross sections for the Fe^(23+)line emission 3_(d5/2)→2_(p3/2)are calculated.The calculation involves line formation by direct electr...By using the semi-relativistic distorted-wave Born exchange method,electron impact cross sections for the Fe^(23+)line emission 3_(d5/2)→2_(p3/2)are calculated.The calculation involves line formation by direct electron-impact excitation,radiative cascade,resonant excitation,and dielectronic recombination satellites with captured electron in the n≥5 levels.The results show a good agreement with the recent measurements.展开更多
An all solid-state pulsed power generator for plasma immersion ion implantation （PIII） is described. The pulsed power system is based on a Marx circuit configuration and semi- conductor switches, which have many adv...An all solid-state pulsed power generator for plasma immersion ion implantation （PIII） is described. The pulsed power system is based on a Marx circuit configuration and semi- conductor switches, which have many advantages in adjustable repetition frequency, pulse width modulation and long serving life compared with the conventional circuit category, tube-based technologies such as gridded vacuum tubes, thyratrons, pulse forming networks and transformers. The operation of PIII with pulse repetition frequencies up to 500 Hz has been achieved at a pulse voltage amplitude from 2 kV to 60 kV, with an adjustable pulse duration from 1 μs to 100 μs. The proposed system and its performance, as used to drive a plasma ion implantation chamber, are described in detail on the basis of the experimental results.展开更多
The crystallography and morphology of precipitate particles in a Cu matrix were studied using an aged Cu–Cr–Zr alloy by transmission electron microscopy（TEM） and high-resolution transmission electron microscopy（H...The crystallography and morphology of precipitate particles in a Cu matrix were studied using an aged Cu–Cr–Zr alloy by transmission electron microscopy（TEM） and high-resolution transmission electron microscopy（HRTEM）. The tensile strength and electrical conductivity of this alloy after various aging processes were tested. The results show that two kinds of crystallographic structure associated with chromium-rich phases, fcc and bcc structure, exist in the peak-aging of the alloy. The orientation relationship between bcc Cr precipitate and the matrix exhibits Nishiyama–Wasserman orientation relationship. Two kinds of Zr-rich phases（Cu4Zr and Cu5Zr）can be identified and the habit plane is parallel to {111}Cu plane during the aging. The increase in strength is ascribed to the precipitation of Cr- and Zr-rich phase.展开更多
文摘TiNi shape memory alloy porosint, a promising artificial bone material, was prepared by self propagating high temperature synthesis method. It is found that the key technical parameter affecting the porosity, the shape and distribution of the bores in the synthesized product is the pre heating temperature of green compact. While the pre heating temperature varies between 523 K and 673 K, the TiNi shape memory alloy porosint with wholly homogeneously distributing bores will be gained. The porosity of the porosint is 70% when the pre heating temperature is near 673 K, which is maximal under different pre heating temperatures. The compressive strength of TiNi SMA porosint with a porosity of 70% manufactured by SHS is up to 100 MPa and the percentage recovered is 92%.
基金Supported by the National Natural Science Foundation of China under Grant No.19774016,China Postdoctoral Science Foun dation,and a research grant from the China Academy of Engineering and Physics.
文摘By using the semi-relativistic distorted-wave Born exchange method,electron impact cross sections for the Fe^(23+)line emission 3_(d5/2)→2_(p3/2)are calculated.The calculation involves line formation by direct electron-impact excitation,radiative cascade,resonant excitation,and dielectronic recombination satellites with captured electron in the n≥5 levels.The results show a good agreement with the recent measurements.
基金supported by National Natural Science Foundation of China (Nos. 50437020, 10675049)
文摘An all solid-state pulsed power generator for plasma immersion ion implantation （PIII） is described. The pulsed power system is based on a Marx circuit configuration and semi- conductor switches, which have many advantages in adjustable repetition frequency, pulse width modulation and long serving life compared with the conventional circuit category, tube-based technologies such as gridded vacuum tubes, thyratrons, pulse forming networks and transformers. The operation of PIII with pulse repetition frequencies up to 500 Hz has been achieved at a pulse voltage amplitude from 2 kV to 60 kV, with an adjustable pulse duration from 1 μs to 100 μs. The proposed system and its performance, as used to drive a plasma ion implantation chamber, are described in detail on the basis of the experimental results.
基金financially supported by the Special Foundation for Technology Research and Development in Research Institute of China (No. 2011DIA5k023)
文摘The crystallography and morphology of precipitate particles in a Cu matrix were studied using an aged Cu–Cr–Zr alloy by transmission electron microscopy（TEM） and high-resolution transmission electron microscopy（HRTEM）. The tensile strength and electrical conductivity of this alloy after various aging processes were tested. The results show that two kinds of crystallographic structure associated with chromium-rich phases, fcc and bcc structure, exist in the peak-aging of the alloy. The orientation relationship between bcc Cr precipitate and the matrix exhibits Nishiyama–Wasserman orientation relationship. Two kinds of Zr-rich phases（Cu4Zr and Cu5Zr）can be identified and the habit plane is parallel to {111}Cu plane during the aging. The increase in strength is ascribed to the precipitation of Cr- and Zr-rich phase.
