The longitudinal velocity Vl and shear velocity Vs of ultrasonic wave propagated along arbitrary three perpendicular directions of the Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5) bulk metallic glass(Zr/Ti BMG)have b...The longitudinal velocity Vl and shear velocity Vs of ultrasonic wave propagated along arbitrary three perpendicular directions of the Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5) bulk metallic glass(Zr/Ti BMG)have been measured at ambient pressure,under hydrostatic pressure(up to 0.5 GPa)and uniaxial compression(up to 70 MPa)using the pulse echo overlap method.The third order elastic constants and the Grüneisen parameter related to the anharmonic properties were derived and discussed.It was found that the BMG with marked different microstructural characteristics comparing with the amorphous carbon exhibited different behaviours related to shear vibratory under high pressure.展开更多
In situ high pressure x-ray diffraction and electrical resistance experiments on TiB have been carried out by using a diamond anvil cell device. The results revealed that the sample undergoes a first-order phase trans...In situ high pressure x-ray diffraction and electrical resistance experiments on TiB have been carried out by using a diamond anvil cell device. The results revealed that the sample undergoes a first-order phase transition at pressures of 3.5-5.0 Gpa and 4.0-5.5 Gpa for the x-ray diffraction and electrical resistance experiments, respectively. The parameters of the state equation are calculated before and after the phase transition and compared with the values calculated by Mohn et al. [J. Phys. C: Solid State Phys. 21(1988)2829] using the augmented spherical wave method.展开更多
The acoustic velocity,attenuation,and their pressure dependence of a bulk metallic glass Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5) have been measured under pressures up to 0.5 GPa at room temperature using the pul...The acoustic velocity,attenuation,and their pressure dependence of a bulk metallic glass Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5) have been measured under pressures up to 0.5 GPa at room temperature using the pulse echo overlap method.The sample was prepared from melt by quenching into liquid nitrogen.Bulk modulus,Young’s modulus,shear modulus,and Poisson’s ratio were derived,other elastic properties and vibrational anharmonicity were also discussed.展开更多
A high-throughput Haman notch filter set has been manufactured and used to collect the Raman scattering signals of pressure-hiduced phase transitions of solid benzene in a diamond anvil cell up to 15 GPa at room tempe...A high-throughput Haman notch filter set has been manufactured and used to collect the Raman scattering signals of pressure-hiduced phase transitions of solid benzene in a diamond anvil cell up to 15 GPa at room temperature.The changes in the profiles as well as the frequencies of Raman scattering spectra are observed and enable us to determine the phase transition.展开更多
The sound velocities of longitudinal and shear waves are measured on a polycrystalline MgB_(2) superconductor with Tc of 39 K. The specimen used in the experiments is pressed and heated using the MgB_(2) powder. The e...The sound velocities of longitudinal and shear waves are measured on a polycrystalline MgB_(2) superconductor with Tc of 39 K. The specimen used in the experiments is pressed and heated using the MgB_(2) powder. The elastic moduli, Debye temperature and specific heat at room temperature are obtained based on sound velocity data. The results indicate that the velocities are much higher than those in the usual materials, while elastic constants remain reasonably soft, which may be due to the high transition temperature of the MgB2 superconductor.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos.19874075 and 59871059.
文摘The longitudinal velocity Vl and shear velocity Vs of ultrasonic wave propagated along arbitrary three perpendicular directions of the Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5) bulk metallic glass(Zr/Ti BMG)have been measured at ambient pressure,under hydrostatic pressure(up to 0.5 GPa)and uniaxial compression(up to 70 MPa)using the pulse echo overlap method.The third order elastic constants and the Grüneisen parameter related to the anharmonic properties were derived and discussed.It was found that the BMG with marked different microstructural characteristics comparing with the amorphous carbon exhibited different behaviours related to shear vibratory under high pressure.
文摘In situ high pressure x-ray diffraction and electrical resistance experiments on TiB have been carried out by using a diamond anvil cell device. The results revealed that the sample undergoes a first-order phase transition at pressures of 3.5-5.0 Gpa and 4.0-5.5 Gpa for the x-ray diffraction and electrical resistance experiments, respectively. The parameters of the state equation are calculated before and after the phase transition and compared with the values calculated by Mohn et al. [J. Phys. C: Solid State Phys. 21(1988)2829] using the augmented spherical wave method.
基金Supported in part by the National Natural Science Foundation of China under Grant No.49374209.
文摘The acoustic velocity,attenuation,and their pressure dependence of a bulk metallic glass Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5) have been measured under pressures up to 0.5 GPa at room temperature using the pulse echo overlap method.The sample was prepared from melt by quenching into liquid nitrogen.Bulk modulus,Young’s modulus,shear modulus,and Poisson’s ratio were derived,other elastic properties and vibrational anharmonicity were also discussed.
基金Supported by the National Natural Science Foundation of China.
文摘A high-throughput Haman notch filter set has been manufactured and used to collect the Raman scattering signals of pressure-hiduced phase transitions of solid benzene in a diamond anvil cell up to 15 GPa at room temperature.The changes in the profiles as well as the frequencies of Raman scattering spectra are observed and enable us to determine the phase transition.
基金Supported by the Outstanding Youth Fund of the National Natural Science Foundation of China under Grant No.59725105the“Hundreds of Talents”Programme of the Chinese Academy of Sciences。
文摘The sound velocities of longitudinal and shear waves are measured on a polycrystalline MgB_(2) superconductor with Tc of 39 K. The specimen used in the experiments is pressed and heated using the MgB_(2) powder. The elastic moduli, Debye temperature and specific heat at room temperature are obtained based on sound velocity data. The results indicate that the velocities are much higher than those in the usual materials, while elastic constants remain reasonably soft, which may be due to the high transition temperature of the MgB2 superconductor.
