用锌-琥珀酸铵饱和水溶液组合成还原体系,以偶氮苯作为原料来制备氢化偶氮苯。实验结果表明:偶氮苯与锌粉物质的量之比为1:6.0(偶氮苯1.25 mmol),饱和琥珀酸铵溶液用量为4.0 m L时为最佳反应条件,反应时间大约3 min,平均产率为91.51%。...用锌-琥珀酸铵饱和水溶液组合成还原体系,以偶氮苯作为原料来制备氢化偶氮苯。实验结果表明:偶氮苯与锌粉物质的量之比为1:6.0(偶氮苯1.25 mmol),饱和琥珀酸铵溶液用量为4.0 m L时为最佳反应条件,反应时间大约3 min,平均产率为91.51%。对产品进行熔点测定及红外光谱分析。展开更多
In order to clarify the role of organic matter in the enrichment of base metal, 10 samples of the Permian Kupferschiefer from southwestern Poland were analyzed by using microscopic and geochemical methods. The results...In order to clarify the role of organic matter in the enrichment of base metal, 10 samples of the Permian Kupferschiefer from southwestern Poland were analyzed by using microscopic and geochemical methods. The results indicate that the solvent extracts have been depleted in the samples with high Cu, Pb, Zn contents. This depletion occurred preferably in saturated hydrocarbons. Saturated hydrocarbons served as hydrogen donor for thermochemical sulfate reduction (TSR). The GC traces of saturated hydrocarbon show that the depletion occurred mainly in long chain n alkanes.展开更多
Monodisperse nonstoichiometric zinc ferrite nanoparticles with a tunable size of 4.1–32.2 nm are fabricated via thermal decomposition. An extrinsic impurity phase of the ZnO component is present in the zinc ferrite n...Monodisperse nonstoichiometric zinc ferrite nanoparticles with a tunable size of 4.1–32.2 nm are fabricated via thermal decomposition. An extrinsic impurity phase of the ZnO component is present in the zinc ferrite nanoparticles with a size of <10 nm, but this phase can be eliminated after the air annealing treatment. The atom ratio of Zn/Fe and concentration of oxygen vacancies decrease as the particle size of zinc ferrite increases, causing magnetic transition from superparamagnetism to ferromagnetism. The X-ray magnetic circular dichroism spectra reveal that the spin magnetic moments of Fe^(3+)are reduced, and the orbital magnetic moments are frozen with the increasing atom ratio of Zn/Fe. Therefore,saturation magnetization decreases. The saturation magnetizations of all the zinc ferrite nanoparticles decrease after the air annealing treatment, suggesting that oxygen vacancies considerably influence the magnetic properties. The air annealing treatment can minimize the number of oxygen defects,which trigger some of the Fe^(3+)–OV–Fe^(3+)ferrimagnetic couplings to transfer into the Fe^(3+)–O^(2-)–Fe^(3+)antiferromagnetic couplings. This work provides new insights regarding the magnetic performance of spinel ferrites by tuning the stoichiometric ratio and oxygen defects.展开更多
文摘In order to clarify the role of organic matter in the enrichment of base metal, 10 samples of the Permian Kupferschiefer from southwestern Poland were analyzed by using microscopic and geochemical methods. The results indicate that the solvent extracts have been depleted in the samples with high Cu, Pb, Zn contents. This depletion occurred preferably in saturated hydrocarbons. Saturated hydrocarbons served as hydrogen donor for thermochemical sulfate reduction (TSR). The GC traces of saturated hydrocarbon show that the depletion occurred mainly in long chain n alkanes.
基金financially supported by the National Natural Science Foundation of China (51572218,11504293 and 11904275)the Natural Science Foundation of Shaanxi Province (2019JM-138)+1 种基金the Scientific Research Program Funded by Shaanxi Provincial Education Department (18JK0786,19JK0413 and 20JK0946)the Key Project of Research and Development of Shaanxi Province (2018ZDCXL-GY-08-05)。
文摘Monodisperse nonstoichiometric zinc ferrite nanoparticles with a tunable size of 4.1–32.2 nm are fabricated via thermal decomposition. An extrinsic impurity phase of the ZnO component is present in the zinc ferrite nanoparticles with a size of <10 nm, but this phase can be eliminated after the air annealing treatment. The atom ratio of Zn/Fe and concentration of oxygen vacancies decrease as the particle size of zinc ferrite increases, causing magnetic transition from superparamagnetism to ferromagnetism. The X-ray magnetic circular dichroism spectra reveal that the spin magnetic moments of Fe^(3+)are reduced, and the orbital magnetic moments are frozen with the increasing atom ratio of Zn/Fe. Therefore,saturation magnetization decreases. The saturation magnetizations of all the zinc ferrite nanoparticles decrease after the air annealing treatment, suggesting that oxygen vacancies considerably influence the magnetic properties. The air annealing treatment can minimize the number of oxygen defects,which trigger some of the Fe^(3+)–OV–Fe^(3+)ferrimagnetic couplings to transfer into the Fe^(3+)–O^(2-)–Fe^(3+)antiferromagnetic couplings. This work provides new insights regarding the magnetic performance of spinel ferrites by tuning the stoichiometric ratio and oxygen defects.
