In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been Performed by using diamond anvil cell with synchrotron radiat...In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been Performed by using diamond anvil cell with synchrotron radiation.The results show that the structure of layered perovskite-like manganate Ca3Mn2O7 is unstable under pressure due to the easy compression of NaCl-type blocks.The structure of Ca3Mn2O7 underwent two phase transitions under pressures in the range of 0-35GPa.One was at about 1.3GPa with the crystal structure changing from tetragonalt go orthorhombic.The other was at about 9.5GPa with the crystal structure changing form orthorhombic back to another tetragonal.展开更多
The compression behaviour of Pd39Ni10Cu30P21 bulk metallic glass is ivestigated at room temperature up to 23.5GPa using in situ high pressure energy dispersive x-ray diffraction with a synchrotron radiation source.Pre...The compression behaviour of Pd39Ni10Cu30P21 bulk metallic glass is ivestigated at room temperature up to 23.5GPa using in situ high pressure energy dispersive x-ray diffraction with a synchrotron radiation source.Pressure induced strucural relaxation of the bulk metallic glass is exhibited within the pressure range.It is found that below about 5GPa,the existence of excess free volume contributes to rapid structural relaxation,which gives rise to rapid volumetic change.Under higher pressure,further relaxation results in structural stiffness.展开更多
We have shown that,in contrast to the results in the literature,the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier el...We have shown that,in contrast to the results in the literature,the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier element(Cu).The atomic density at Ni80Fe20/Cu interface was analysed by the diffraction anomalous fine structure technology with the incident angle of x-ray fixed at the first Bragg peak.Our results demonstrate the epitaxy growth of Ni80Fe20/Cu superlattices.Upon annealing,the epitaxity of Ni80Fe20/Cu multilayers becomes poor but the local crystallinity in each layer is improved.展开更多
Double-walled carbon nanotubes were prepared using the floating chemical vapor deposition with methane as carbon source and adding small amount of sulfur into the ferrocene catalyst. The optimized technological parame...Double-walled carbon nanotubes were prepared using the floating chemical vapor deposition with methane as carbon source and adding small amount of sulfur into the ferrocene catalyst. The optimized technological parameters are: the reaction temperature is 1200℃; the catalyst vapor temperature is 80℃; the flow rate of argon is 2000 SCCM; the flow rate of methane is 5 SCCM. The purified DWNTs under these optimized technological parameters have high purity above 90 wt%.展开更多
Nanosecond laser pulse photolysis was used to investigate the excited-state dynamics of the photonuclease vitamin-K3 (VK3). A spectral band peaked at 285 nm was newly observed and attributed to the triplet-excited sta...Nanosecond laser pulse photolysis was used to investigate the excited-state dynamics of the photonuclease vitamin-K3 (VK3). A spectral band peaked at 285 nm was newly observed and attributed to the triplet-excited state of VK3. In studying the photochemistry between the photonu-clease VK3 and guanine nucleotide (dGMP), we obtained spectroscopic evidence for the photo-initiated formation of both VK3 radical anion and dGMP radical cation, and thus proved the charge transfer reaction between the trip-let-excited VK3 and the ground-state dGMP.展开更多
文摘In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been Performed by using diamond anvil cell with synchrotron radiation.The results show that the structure of layered perovskite-like manganate Ca3Mn2O7 is unstable under pressure due to the easy compression of NaCl-type blocks.The structure of Ca3Mn2O7 underwent two phase transitions under pressures in the range of 0-35GPa.One was at about 1.3GPa with the crystal structure changing from tetragonalt go orthorhombic.The other was at about 9.5GPa with the crystal structure changing form orthorhombic back to another tetragonal.
文摘The compression behaviour of Pd39Ni10Cu30P21 bulk metallic glass is ivestigated at room temperature up to 23.5GPa using in situ high pressure energy dispersive x-ray diffraction with a synchrotron radiation source.Pressure induced strucural relaxation of the bulk metallic glass is exhibited within the pressure range.It is found that below about 5GPa,the existence of excess free volume contributes to rapid structural relaxation,which gives rise to rapid volumetic change.Under higher pressure,further relaxation results in structural stiffness.
文摘We have shown that,in contrast to the results in the literature,the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier element(Cu).The atomic density at Ni80Fe20/Cu interface was analysed by the diffraction anomalous fine structure technology with the incident angle of x-ray fixed at the first Bragg peak.Our results demonstrate the epitaxy growth of Ni80Fe20/Cu superlattices.Upon annealing,the epitaxity of Ni80Fe20/Cu multilayers becomes poor but the local crystallinity in each layer is improved.
文摘Double-walled carbon nanotubes were prepared using the floating chemical vapor deposition with methane as carbon source and adding small amount of sulfur into the ferrocene catalyst. The optimized technological parameters are: the reaction temperature is 1200℃; the catalyst vapor temperature is 80℃; the flow rate of argon is 2000 SCCM; the flow rate of methane is 5 SCCM. The purified DWNTs under these optimized technological parameters have high purity above 90 wt%.
文摘Nanosecond laser pulse photolysis was used to investigate the excited-state dynamics of the photonuclease vitamin-K3 (VK3). A spectral band peaked at 285 nm was newly observed and attributed to the triplet-excited state of VK3. In studying the photochemistry between the photonu-clease VK3 and guanine nucleotide (dGMP), we obtained spectroscopic evidence for the photo-initiated formation of both VK3 radical anion and dGMP radical cation, and thus proved the charge transfer reaction between the trip-let-excited VK3 and the ground-state dGMP.
