The effects of alloying elements P and Cu on the sintering process and mechanical properties of short cast iron fiber compact have been studied. The experimental results show that the sintering can be enhanced obvious...The effects of alloying elements P and Cu on the sintering process and mechanical properties of short cast iron fiber compact have been studied. The experimental results show that the sintering can be enhanced obviously by addition of phosphorus. The radial crush strength of sintered compacts increases with P content up to 0.15%, but when P content is over 0.15%, eutectics formed at the interfaces of fibers cause the decrease in strength and quasi-cleavage fracture of the sintered compact. Addition of Cu could not only reduce the volume shrinkage effectively, but also increase the strength and hardness of the sintered compact.展开更多
C-N thin films have been prepared by ion beam sputtering using pure N-2 as discharge gas. The ratio N/C of the films measured by Auger spectrum is 20% on an average. The results of X-ray diffraction and transmission e...C-N thin films have been prepared by ion beam sputtering using pure N-2 as discharge gas. The ratio N/C of the films measured by Auger spectrum is 20% on an average. The results of X-ray diffraction and transmission electron microscopy show that beta-C3N4. phase exists in the films. X-ray photoelectron spectroscopy shows that nitrogen is mostly combined with carbon with triple (C=N) and double (C=N) bonds. The IR absorption shows an absorption bond near 2185 cm(-1) assigned to the C=N, no trace of C-C bond was observed.展开更多
The liquid sintering characteristics have been studied in the sintered compacts of short cast iron fibers added with Ni-Cr based alloy powder at the sintering temperature of 1100 degrees C. With the increase of Ni-Cr ...The liquid sintering characteristics have been studied in the sintered compacts of short cast iron fibers added with Ni-Cr based alloy powder at the sintering temperature of 1100 degrees C. With the increase of Ni-Cr based alloy content, the microstructure of sintered compact of short cast iron fibers transformed from pearlite + ferrite to martensite + austenite, meanwhile volume expansion appeared in the sintered compact, leading to more pores. The proper addition of P-Fe powder could restrain the expansion of the sintered compact and increase the strength and hardness of the sintered compact.展开更多
RECENTLY, frequency selective excitation was extensively studied and applied successfullyto various types of nuclear magnetic resonance (NMR) experiments. Solvent suppression,double resonance, multiple quantum coheren...RECENTLY, frequency selective excitation was extensively studied and applied successfullyto various types of nuclear magnetic resonance (NMR) experiments. Solvent suppression,double resonance, multiple quantum coherence, as well as multi-dimensional NMR are all re-lated to selective excitation. Probably, its most important application is in NMR imaging.Nowadays, selective excitation unit (SEU) has become an important accessory in modernNMR spectrometer.展开更多
文摘The effects of alloying elements P and Cu on the sintering process and mechanical properties of short cast iron fiber compact have been studied. The experimental results show that the sintering can be enhanced obviously by addition of phosphorus. The radial crush strength of sintered compacts increases with P content up to 0.15%, but when P content is over 0.15%, eutectics formed at the interfaces of fibers cause the decrease in strength and quasi-cleavage fracture of the sintered compact. Addition of Cu could not only reduce the volume shrinkage effectively, but also increase the strength and hardness of the sintered compact.
文摘C-N thin films have been prepared by ion beam sputtering using pure N-2 as discharge gas. The ratio N/C of the films measured by Auger spectrum is 20% on an average. The results of X-ray diffraction and transmission electron microscopy show that beta-C3N4. phase exists in the films. X-ray photoelectron spectroscopy shows that nitrogen is mostly combined with carbon with triple (C=N) and double (C=N) bonds. The IR absorption shows an absorption bond near 2185 cm(-1) assigned to the C=N, no trace of C-C bond was observed.
文摘The liquid sintering characteristics have been studied in the sintered compacts of short cast iron fibers added with Ni-Cr based alloy powder at the sintering temperature of 1100 degrees C. With the increase of Ni-Cr based alloy content, the microstructure of sintered compact of short cast iron fibers transformed from pearlite + ferrite to martensite + austenite, meanwhile volume expansion appeared in the sintered compact, leading to more pores. The proper addition of P-Fe powder could restrain the expansion of the sintered compact and increase the strength and hardness of the sintered compact.
文摘RECENTLY, frequency selective excitation was extensively studied and applied successfullyto various types of nuclear magnetic resonance (NMR) experiments. Solvent suppression,double resonance, multiple quantum coherence, as well as multi-dimensional NMR are all re-lated to selective excitation. Probably, its most important application is in NMR imaging.Nowadays, selective excitation unit (SEU) has become an important accessory in modernNMR spectrometer.
