Magnetic properties of nanocrystalline Fe_~60 Cr_~40 powders prepared by mechanical alloying in vacuum and air were investigated by utilizing the measurements of magnetization, X-ray diffraction, and ~ ~57 Fe Mssbauer...Magnetic properties of nanocrystalline Fe_~60 Cr_~40 powders prepared by mechanical alloying in vacuum and air were investigated by utilizing the measurements of magnetization, X-ray diffraction, and ~ ~57 Fe Mssbauer spectrum. The results show that the Fe_~60 Cr_~40 powders keep the bcc structure during milling in air and vacuum. The saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum and air decreases with the increase of the milling time up to 45 h. The decrease of saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum is due to the formation of Fe-Cr solid solution, while in air it is due to the formation of paramagnetic disorder structure and solid solution.展开更多
The magnetism and content of soil magnetic minerals are the foundation of the soil magnetic genesis research and the application of the soil magnetism to the applied geophysics, archaeology and the environmental scien...The magnetism and content of soil magnetic minerals are the foundation of the soil magnetic genesis research and the application of the soil magnetism to the applied geophysics, archaeology and the environmental science. According to Mssbauer spectra展开更多
^(57)Fe Mssbauer spectroscopy was used to study the mechanism and regularity of coal desulfurization by microwave irradiation combined with magnetic-separation and with chemical acid-leaching. The results of phase ana...^(57)Fe Mssbauer spectroscopy was used to study the mechanism and regularity of coal desulfurization by microwave irradiation combined with magnetic-separation and with chemical acid-leaching. The results of phase analyses show that the decomposing reaction of pyrite intrinsic in coal, caused by the selective dielectric heating of microwave electromagnetic energy, FeS_2→Fe_(1-x)S→FeS, consecutively progresses towards the right-hand side with increased irradiation time. The whole process of microwave desulfurization of raw coal consists of the initiation, the promotion, and the saturation stages. The optimum desulfurization efficiency for microwave irradiation combined with magnetic-separation treatment and with chemical acid-leaching treatment can be attained by appropriately controlling the irradiation time to enable the corresponding microwave treatment to lie in the promotion stage and the saturation stage, respectively.展开更多
文摘Magnetic properties of nanocrystalline Fe_~60 Cr_~40 powders prepared by mechanical alloying in vacuum and air were investigated by utilizing the measurements of magnetization, X-ray diffraction, and ~ ~57 Fe Mssbauer spectrum. The results show that the Fe_~60 Cr_~40 powders keep the bcc structure during milling in air and vacuum. The saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum and air decreases with the increase of the milling time up to 45 h. The decrease of saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum is due to the formation of Fe-Cr solid solution, while in air it is due to the formation of paramagnetic disorder structure and solid solution.
基金Project supported by the National Natural Science Foundation of China.
文摘The magnetism and content of soil magnetic minerals are the foundation of the soil magnetic genesis research and the application of the soil magnetism to the applied geophysics, archaeology and the environmental science. According to Mssbauer spectra
文摘^(57)Fe Mssbauer spectroscopy was used to study the mechanism and regularity of coal desulfurization by microwave irradiation combined with magnetic-separation and with chemical acid-leaching. The results of phase analyses show that the decomposing reaction of pyrite intrinsic in coal, caused by the selective dielectric heating of microwave electromagnetic energy, FeS_2→Fe_(1-x)S→FeS, consecutively progresses towards the right-hand side with increased irradiation time. The whole process of microwave desulfurization of raw coal consists of the initiation, the promotion, and the saturation stages. The optimum desulfurization efficiency for microwave irradiation combined with magnetic-separation treatment and with chemical acid-leaching treatment can be attained by appropriately controlling the irradiation time to enable the corresponding microwave treatment to lie in the promotion stage and the saturation stage, respectively.
