Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and with...Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and without extrusion process.The influences of microstructure evolution,introduced by DC casting and thermal-mechanical processing,on the hydrogen storage performance of Mg-Ni-Gd-Y-ZnCu alloys were comprehensively explored,using analytical electron microscopy and in-situ synchrotron powder X-ray diffraction.The result shows that the extruded alloy yields higher hydrogen absorption capacity and faster hydrogen ab/desorption kinetics.As subjected to extrusion processing,theα-Mg grains in the microstructure were significantly refined and a large number of 14H type long-period stacking ordered(LPSO)phases appeared on theα-Mg matrix.After activation,there were more nanosized Gd hydride/Mg2Ni intermetallics and finer chips.These modifications synergistically enhance the hydrogen storage properties.The findings have implications for the alloy design and manufacturing of magnesiumbased hydrogen storage materials with the advantages of rapid mass production and anti-oxidation.展开更多
The broadening effect of stacking disorder in hexagonal graphite is found experimentally by XRD to be identical to that of stacking faults in hexagonal-closed-packing(HCP) structure,which has obvious selective broaden...The broadening effect of stacking disorder in hexagonal graphite is found experimentally by XRD to be identical to that of stacking faults in hexagonal-closed-packing(HCP) structure,which has obvious selective broadening effect.The Langford's method for dealing with the twofold broadening effects of the crystallite-faults in hexagonal ZnO has been extended in this paper,and then applied to the deter-mination of stacking disorder in 2H-graphite,which indicates that our extension method is convenient to both the experiments and data process,and may be generalized further.Two stacking disorder model in 2H-graphite and data processing method have been proposed in this study.The two disorder degrees of PAB and PABC can be computed when the two reliable FWHMs of 101 and 102 diffraction peaks were obtained.展开更多
Synchisite-(Ce) from the Kibina alkaline massive, Kola peninsula, Russia , has been studied using electron diffraction and lattice-images techniques. The synchisite-(Ce) with relatively ordered stacking shows a microt...Synchisite-(Ce) from the Kibina alkaline massive, Kola peninsula, Russia , has been studied using electron diffraction and lattice-images techniques. The synchisite-(Ce) with relatively ordered stacking shows a microtwin. The semirandom stacking is caused by the displacement of CO3 layers parallel to the basal planes. The irregular stacking crystals contain Ca layers adjacent to each other.The synchisite-(Ce) is considered as a polymatic mineral with short-range disorder.展开更多
Line broadening in a diffraction intensity profile of powdered crystalline materials due to stacking fault has been characterized in terms of the zeroth, first, second, third, and fourth moments and the fourth cumulan...Line broadening in a diffraction intensity profile of powdered crystalline materials due to stacking fault has been characterized in terms of the zeroth, first, second, third, and fourth moments and the fourth cumulant. Calculations have been derived showing that the first moment causes a shift in the peak position of the profile while the third moment affects its shape. The intensity expression has been derived on the basis of usual Cartesian coordinates and also of polar coordinates indicated by the probability of the fault and the reciprocal lattice parameter as the two axes. The expressions for the fourth cumulant have also been so derived. Here we have used three different approaches to determine methods for calculating the fourth cumulant due to stacking faults. The three forms of the equations derived here are for different coordinate systems, but will arrive at the same answers.展开更多
Compound 1 （5-hydroxy-6-methoxybenzofuran-3-yl）（4-methoxyphenyl）metha- none, C17H1405, as a potential anti-breast cancer agent has been synthesized under microwave irradiation, which was further converted to （5,6...Compound 1 （5-hydroxy-6-methoxybenzofuran-3-yl）（4-methoxyphenyl）metha- none, C17H1405, as a potential anti-breast cancer agent has been synthesized under microwave irradiation, which was further converted to （5,6-dihydroxybenzofuran-3-yl）（4-methoxyphenyi）me- thanone （2）. The compounds were characterized by MS and NMR spectra. Meanwhile, the crystal of 1 was obtained and determined by X-ray single-crystal diffraction. Crystal data： monoclinic system, space group P2/n, a = 8.908（6）, b = 10.505（7）, c = 15.452（11） A, β = 105.043（9）, V = 1396.4（16） A3, Z = 4, F（000） = 624, Dc = 1.419 g/cm3, p = 0.105 mm-1, R = 0.0513 and wR = 0.1246 for 14459 independent reflections （Rint = 0.0647） and 2488 observed ones （I〉 2σ（/））. lntermolecular O-H...O and π-π stacking interactions contributed to the stability of the structure.展开更多
基金synchrotron PXRD experiment was conducted at the Powder Diffraction beamline,ANSTO Australian Synchrotron under proposal Nos.AS211/PD/16842 and AS221/PD/17948G.Z.acknowledges the funding from the National Natural Science Foundation of China(No.51904352)Scientific Research Foundation of Hunan Provincial Education Department,China(No.22A0004)。
文摘Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and without extrusion process.The influences of microstructure evolution,introduced by DC casting and thermal-mechanical processing,on the hydrogen storage performance of Mg-Ni-Gd-Y-ZnCu alloys were comprehensively explored,using analytical electron microscopy and in-situ synchrotron powder X-ray diffraction.The result shows that the extruded alloy yields higher hydrogen absorption capacity and faster hydrogen ab/desorption kinetics.As subjected to extrusion processing,theα-Mg grains in the microstructure were significantly refined and a large number of 14H type long-period stacking ordered(LPSO)phases appeared on theα-Mg matrix.After activation,there were more nanosized Gd hydride/Mg2Ni intermetallics and finer chips.These modifications synergistically enhance the hydrogen storage properties.The findings have implications for the alloy design and manufacturing of magnesiumbased hydrogen storage materials with the advantages of rapid mass production and anti-oxidation.
基金Supported by the National Natural Science Foundation of China (Grant No. 20773157)
文摘The broadening effect of stacking disorder in hexagonal graphite is found experimentally by XRD to be identical to that of stacking faults in hexagonal-closed-packing(HCP) structure,which has obvious selective broadening effect.The Langford's method for dealing with the twofold broadening effects of the crystallite-faults in hexagonal ZnO has been extended in this paper,and then applied to the deter-mination of stacking disorder in 2H-graphite,which indicates that our extension method is convenient to both the experiments and data process,and may be generalized further.Two stacking disorder model in 2H-graphite and data processing method have been proposed in this study.The two disorder degrees of PAB and PABC can be computed when the two reliable FWHMs of 101 and 102 diffraction peaks were obtained.
文摘Synchisite-(Ce) from the Kibina alkaline massive, Kola peninsula, Russia , has been studied using electron diffraction and lattice-images techniques. The synchisite-(Ce) with relatively ordered stacking shows a microtwin. The semirandom stacking is caused by the displacement of CO3 layers parallel to the basal planes. The irregular stacking crystals contain Ca layers adjacent to each other.The synchisite-(Ce) is considered as a polymatic mineral with short-range disorder.
文摘Line broadening in a diffraction intensity profile of powdered crystalline materials due to stacking fault has been characterized in terms of the zeroth, first, second, third, and fourth moments and the fourth cumulant. Calculations have been derived showing that the first moment causes a shift in the peak position of the profile while the third moment affects its shape. The intensity expression has been derived on the basis of usual Cartesian coordinates and also of polar coordinates indicated by the probability of the fault and the reciprocal lattice parameter as the two axes. The expressions for the fourth cumulant have also been so derived. Here we have used three different approaches to determine methods for calculating the fourth cumulant due to stacking faults. The three forms of the equations derived here are for different coordinate systems, but will arrive at the same answers.
基金Supported by the National Natural Science Foundation of China(No.21102084)Scientific and Technological Research Project of Hubei Provincial Department of Education(Q20111210)Science Foundation of China Three Gorges University(Nos.KJ2009B046and KJ2010B001)
文摘Compound 1 （5-hydroxy-6-methoxybenzofuran-3-yl）（4-methoxyphenyl）metha- none, C17H1405, as a potential anti-breast cancer agent has been synthesized under microwave irradiation, which was further converted to （5,6-dihydroxybenzofuran-3-yl）（4-methoxyphenyi）me- thanone （2）. The compounds were characterized by MS and NMR spectra. Meanwhile, the crystal of 1 was obtained and determined by X-ray single-crystal diffraction. Crystal data： monoclinic system, space group P2/n, a = 8.908（6）, b = 10.505（7）, c = 15.452（11） A, β = 105.043（9）, V = 1396.4（16） A3, Z = 4, F（000） = 624, Dc = 1.419 g/cm3, p = 0.105 mm-1, R = 0.0513 and wR = 0.1246 for 14459 independent reflections （Rint = 0.0647） and 2488 observed ones （I〉 2σ（/））. lntermolecular O-H...O and π-π stacking interactions contributed to the stability of the structure.
