The high-pressure behaviour of the superconductor MgB_(2) with a hexagonal structure has been investigated by the in situ synchrotron radiation x-ray diffraction method under pressures up to 42.2 GPa in a diamond anvi...The high-pressure behaviour of the superconductor MgB_(2) with a hexagonal structure has been investigated by the in situ synchrotron radiation x-ray diffraction method under pressures up to 42.2 GPa in a diamond anvil cell. An abrupt decrease of about 7% in the unit cell volume of this material occurs in the pressure range of 26.3-30.2 GPa. A split of the Raman spectrum was also observed. The jump of the compression curve and Raman spectrum are ascribed to an isostructural transition in MgB_(2 ) at a pressure of 30.2 GPa.展开更多
The Pd_(39)Ni_(10)Cu_(30)P_(21) bulk metallic glass is isothermally relaxed under various pressures.The degree of the structural relaxation is evaluated in terms of the enthalpy recovery behaviours involved in the irr...The Pd_(39)Ni_(10)Cu_(30)P_(21) bulk metallic glass is isothermally relaxed under various pressures.The degree of the structural relaxation is evaluated in terms of the enthalpy recovery behaviours involved in the irreversible glass transition processes by using a temperature-modulated differential scanning calarimetry technique.A roughly linear increase of the recovery enthalpy is observed within the experimental pressure range from 2.67 to 4.45 GPa,which reflects the release of the frozen-in enthalpy in the as-quenched glass with increasing relaxation pressure.The pressure dependence of the time scale of the enthalpy recovery processes is also exhibited.展开更多
Hypervelocity impact on rectangular plate-shaped Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass(BMG)is performed by a two−stage light gas gun.The targets used in the experiment are BMG plates with a thickness of 5 mm.Th...Hypervelocity impact on rectangular plate-shaped Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass(BMG)is performed by a two−stage light gas gun.The targets used in the experiment are BMG plates with a thickness of 5 mm.The projectile,spherical aluminum(3.1 mm in diameter),is accelerated up to various velocities;the light is detected with a radiometer.The emission lasts from 200µs up to 1500µs and the intensity increases from 44 to 900 W/(Sr⋅µm).The duration and intensity of a light emission seem to depend on the impact velocity and the extent of target destruction through the formation of impact craters or penetration.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.10004014the synchrotron radiation experiments were carried out under Approval No.2001PF-03 of the Photon Factory.
文摘The high-pressure behaviour of the superconductor MgB_(2) with a hexagonal structure has been investigated by the in situ synchrotron radiation x-ray diffraction method under pressures up to 42.2 GPa in a diamond anvil cell. An abrupt decrease of about 7% in the unit cell volume of this material occurs in the pressure range of 26.3-30.2 GPa. A split of the Raman spectrum was also observed. The jump of the compression curve and Raman spectrum are ascribed to an isostructural transition in MgB_(2 ) at a pressure of 30.2 GPa.
基金Supported by the National Natural Science Foundation of China under Grant Nos.59889102,10004014by Chinese National Microgravity Laboratory(Pan-Yu-95-34).
文摘The Pd_(39)Ni_(10)Cu_(30)P_(21) bulk metallic glass is isothermally relaxed under various pressures.The degree of the structural relaxation is evaluated in terms of the enthalpy recovery behaviours involved in the irreversible glass transition processes by using a temperature-modulated differential scanning calarimetry technique.A roughly linear increase of the recovery enthalpy is observed within the experimental pressure range from 2.67 to 4.45 GPa,which reflects the release of the frozen-in enthalpy in the as-quenched glass with increasing relaxation pressure.The pressure dependence of the time scale of the enthalpy recovery processes is also exhibited.
基金by the National Basic Research Program of China(973 Program)under Grant No 2010CB731600.
文摘Hypervelocity impact on rectangular plate-shaped Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass(BMG)is performed by a two−stage light gas gun.The targets used in the experiment are BMG plates with a thickness of 5 mm.The projectile,spherical aluminum(3.1 mm in diameter),is accelerated up to various velocities;the light is detected with a radiometer.The emission lasts from 200µs up to 1500µs and the intensity increases from 44 to 900 W/(Sr⋅µm).The duration and intensity of a light emission seem to depend on the impact velocity and the extent of target destruction through the formation of impact craters or penetration.
