Small discs of type HR- 1 austenitic steel (OCr17Ni14MnMo) have been irradiated with 30-170 keV He+ for doses 1015- 1×1018/cm2 at 300K. 2.5 MeV enhanced proton backscattering, TEM, SEM and CEMS are used to invest...Small discs of type HR- 1 austenitic steel (OCr17Ni14MnMo) have been irradiated with 30-170 keV He+ for doses 1015- 1×1018/cm2 at 300K. 2.5 MeV enhanced proton backscattering, TEM, SEM and CEMS are used to investigate the He trapping, bubble structures and the phase stability. It is found that a maximum He concentration of -28 at. % was obtained after implantation with 70 keV He+ at a dose just below critical. The micro- Vickers hardnesses of irradiated layers decrease with increasing dose, particularly when dense bubbles formed. The isomer shift of CEMS increases in the negative direction after irradiation. The austenite is believed to be stable against radiation induced martensitic transformation.展开更多
The ceramic samples with nominal composition of La_(2/3)Ca_(1/3)Fe_(1-x)Mn_(x)O_(3)(0.01≤x≤0.20)were prepared by solid state reaction method.The effect of Fe doping on the Mn site was measured by the positron annihi...The ceramic samples with nominal composition of La_(2/3)Ca_(1/3)Fe_(1-x)Mn_(x)O_(3)(0.01≤x≤0.20)were prepared by solid state reaction method.The effect of Fe doping on the Mn site was measured by the positron annihilation technique and M'dssbauer spectroscopy.Upon doping,no appreciable structure change and electronic structure change in Mn-O plane were observed in the series of compounds.The M6ssbauer parameters show that the iron probe has stable 3+valance with the high spin state in all samples.Moreover,by examining the shape of the spectra,the tendency can be found that the isomer shift and quadruploe splitting increase with the increasing Fe+3 content.This phenomenon shows the local lattice distortion and the localization of d-electrons with the increasing Fe-doping content.展开更多
Recently, 3-Dimension Complementary Metal-Oxide Semiconductor(3-D CMOS)has attracted great interest of many scholars due to its high packing density, simple connection and improved characteristics. The present 3-D CMO...Recently, 3-Dimension Complementary Metal-Oxide Semiconductor(3-D CMOS)has attracted great interest of many scholars due to its high packing density, simple connection and improved characteristics. The present 3-D CMOS consists of an n-channel MOS(NMOS) transistor on a P-type silicon substrate and a p-channel MOS(PMOS) tran-展开更多
Hydrogen promotes the cleavage fracture of Fe-3%Si alloy. Hydrogen atmosphere moving along with a dislocation will reduce the strain energy of the dislocation, resulting in a decrease in the external stress necessary ...Hydrogen promotes the cleavage fracture of Fe-3%Si alloy. Hydrogen atmosphere moving along with a dislocation will reduce the strain energy of the dislocation, resulting in a decrease in the external stress necessary to operate the F-R source. Thus, hydrogen can promote dislocation multication, which has been verified using a dislocation decoration technique. Fractography and mechanic analysis indicate that a set of the [001] sessile dislocations on the {001}-plane is just a cleavage microcrack. Hydrogen carried by the gliding dislocation will enter the microcrack, and the hydrogen pressure will augment the external stress and reduce the critical number n necessary to form a stable cleavage crack and the number m of the pile-up dislocations. This indicates that hydrogen promotes the formation of the stable cleavage crack before the other slip systems operate.展开更多
文摘Small discs of type HR- 1 austenitic steel (OCr17Ni14MnMo) have been irradiated with 30-170 keV He+ for doses 1015- 1×1018/cm2 at 300K. 2.5 MeV enhanced proton backscattering, TEM, SEM and CEMS are used to investigate the He trapping, bubble structures and the phase stability. It is found that a maximum He concentration of -28 at. % was obtained after implantation with 70 keV He+ at a dose just below critical. The micro- Vickers hardnesses of irradiated layers decrease with increasing dose, particularly when dense bubbles formed. The isomer shift of CEMS increases in the negative direction after irradiation. The austenite is believed to be stable against radiation induced martensitic transformation.
基金Supported by the National Natural Science Foundation of China under Grant No.19805010by the Key-project of Chinese Academy of Sciences under contract KJ952-S1-416.
文摘The ceramic samples with nominal composition of La_(2/3)Ca_(1/3)Fe_(1-x)Mn_(x)O_(3)(0.01≤x≤0.20)were prepared by solid state reaction method.The effect of Fe doping on the Mn site was measured by the positron annihilation technique and M'dssbauer spectroscopy.Upon doping,no appreciable structure change and electronic structure change in Mn-O plane were observed in the series of compounds.The M6ssbauer parameters show that the iron probe has stable 3+valance with the high spin state in all samples.Moreover,by examining the shape of the spectra,the tendency can be found that the isomer shift and quadruploe splitting increase with the increasing Fe+3 content.This phenomenon shows the local lattice distortion and the localization of d-electrons with the increasing Fe-doping content.
文摘Recently, 3-Dimension Complementary Metal-Oxide Semiconductor(3-D CMOS)has attracted great interest of many scholars due to its high packing density, simple connection and improved characteristics. The present 3-D CMOS consists of an n-channel MOS(NMOS) transistor on a P-type silicon substrate and a p-channel MOS(PMOS) tran-
文摘Hydrogen promotes the cleavage fracture of Fe-3%Si alloy. Hydrogen atmosphere moving along with a dislocation will reduce the strain energy of the dislocation, resulting in a decrease in the external stress necessary to operate the F-R source. Thus, hydrogen can promote dislocation multication, which has been verified using a dislocation decoration technique. Fractography and mechanic analysis indicate that a set of the [001] sessile dislocations on the {001}-plane is just a cleavage microcrack. Hydrogen carried by the gliding dislocation will enter the microcrack, and the hydrogen pressure will augment the external stress and reduce the critical number n necessary to form a stable cleavage crack and the number m of the pile-up dislocations. This indicates that hydrogen promotes the formation of the stable cleavage crack before the other slip systems operate.
