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Abnormal variation of magnetic properties with Ce content in(PrNdCe)_2Fe_(14)B sintered magnets prepared by dual alloy method 下载免费PDF全文
Resource-saving(PrNdCe)_2Fe_(14)B sintered magnets with nominal composition(PrNd)_(15-x)Ce_xFe_(77)B_8(x=0–10)were prepared using a dual alloy method by mixing(PrNd)_5Ce_(10)Fe_(77)B_8 with(PrNd)_(15)Fe_(77)B_8 powders. For Ce atomic percent of 1% and 2%, coercivity decreases dramatically. With further increase of Ce atomic percent, the coercivity increases, peaks at 6.38 kOe in(PrNd)_(11)Ce_4Fe_(77)B_8, and then declines gradually. The abnormal dependence of coercivity is likely related to the inhomogeneity of rare earth chemical composition in the intergranular phase, where Pr Nd concentration is strongly dependent on the additive amount of(PrNd)_5Ce_(10)Fe_(77)B_8 powders. In addition, for Ce atomic percent of 8%,7%, and 6% the coercivity is higher than that of magnets prepared by the conventional method, which shows the advantage of the dual alloy method in preparing high abundant rare earth magnets. 相似文献
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一种基于BiCMOS工艺的差分压控振荡器 总被引:1,自引:0,他引:1
设计了一种Colpitts型LC振荡器。该电路采用差分结构,具有集成度高,噪声性能良好的优点。该设计基于0.8μm BiCMOS工艺,实现了中心频率为433MHz的Colpitts型差分压控振荡器(VCO)。电路采用3V电压供电,频率范围399.8~465.1MHz,偏离中心频率1MHz处的相位噪声是-137dBc/Hz。 相似文献
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实验测量了0.75 MeV的O5+离子穿过一定长度不同原子数密度H2靶后的电荷态分布;理论模拟了出射离子的平均电荷态以及达到平衡后的平均电荷态,得到了与实验吻合较好的结果。研究表明,随着靶原子数密度的增大,离子在碰撞过程中俘获电子的几率随之增加,平均电荷态降低;当靶原子数密度达到或超过1014 cm-3,入射离子俘获电子和被碰撞电离的两个作用过程达到平衡,出射离子的平衡平均电荷态约为1.2。 相似文献
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本文设计了一种Colpitts型LC振荡器,采用差分结构,具有集成度高、噪声性能良好的优点。该设计基于0.8um BiCMOS工艺,实现了中心频率为433MHz的Colpitts型差分压控振荡器(VCO)。电路采用3V电压供电,频率范围399.8MHz-465.1MHz,偏离中心频率1MHz处的相位噪声是-128.2dBc/Hz。 相似文献
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The magnetic properties of two-dimensional antiferromagnet NiGa2S4have attracted much attention and yet some problems are far from being solved. We investigate the magnetic properties of NiGa2S4by Monte Carlo simulations. A new spin-interacting model is proposed to describe the system, and the specific heat together with the doping effect of nonmagnetic impurity is studied by simulations. The double peaks of the specific heat as well as other behaviors are well reproduced. We also compare our results with those of other models, and the underlying physics is discussed. 相似文献
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介绍了数模混合信号仿真的设计流程,说明了一种在混合设计的各个层次上对系统进行仿真验证的自上而下的设计方法。在PLL(Phase-Locked Loop)系统设计中,给出了VCO的数学模型和Verilog-A行为级模型.实现了系统行为级模型和晶体管级电路的设计和仿真,并对结果进行了比较。这种设计方法已应用于一种电荷泵锁相环电路设计中,验证了这种设计方法的可行性和有效性。 相似文献