金属—EDTA络合物的条件稳定常数是判断一种金属离子能否滴定的依据,也是估量最低滴定pH值以及适合滴定的最低浓度的基础。长期以来,人们在教科书、论文中引用Ringbom在《Complexation in Analytical Chemistry》上的资料。Ringbom不愧...金属—EDTA络合物的条件稳定常数是判断一种金属离子能否滴定的依据,也是估量最低滴定pH值以及适合滴定的最低浓度的基础。长期以来,人们在教科书、论文中引用Ringbom在《Complexation in Analytical Chemistry》上的资料。Ringbom不愧为一代宗师,但由于他的书出版较早(1963年),距今已20余年,未经修订,所引用资料中某些部分难免有问题。例如Bi—EDTA络合物的条件稳定常数对数值,在pH1时为5.3,如此则在pH1滴定铋是不可能的。事实告诉我们却不然。在pH1滴定铋,不但可能,而且终点极为敏锐。展开更多
A compact four-component two-dimensional （2-D） finite-difference frequency domain （FDFD） method with the equivalent surface impedance boundary condition is used to analyze the dispersion characteristics of multila...A compact four-component two-dimensional （2-D） finite-difference frequency domain （FDFD） method with the equivalent surface impedance boundary condition is used to analyze the dispersion characteristics of multilayer metal-coated waveguides. According to the equivalent surface impedance boundary condition,the relationship between transverse field components on the boundary can be easily depicted. Once the eigen equation is solved,the propagation constant can be obtained as the eigen value for a given frequency. Results of the proposed method agaree well with those of high frequency structure simulator（HFSS）.展开更多
文摘金属—EDTA络合物的条件稳定常数是判断一种金属离子能否滴定的依据,也是估量最低滴定pH值以及适合滴定的最低浓度的基础。长期以来,人们在教科书、论文中引用Ringbom在《Complexation in Analytical Chemistry》上的资料。Ringbom不愧为一代宗师,但由于他的书出版较早(1963年),距今已20余年,未经修订,所引用资料中某些部分难免有问题。例如Bi—EDTA络合物的条件稳定常数对数值,在pH1时为5.3,如此则在pH1滴定铋是不可能的。事实告诉我们却不然。在pH1滴定铋,不但可能,而且终点极为敏锐。
基金Supported by the Project Innovation of Graduate Students of Jiangsu Province of China(CX09B-079Z)the Basic Research Items of National Key Lab of Electronic Measurement Technology~~
文摘A compact four-component two-dimensional （2-D） finite-difference frequency domain （FDFD） method with the equivalent surface impedance boundary condition is used to analyze the dispersion characteristics of multilayer metal-coated waveguides. According to the equivalent surface impedance boundary condition,the relationship between transverse field components on the boundary can be easily depicted. Once the eigen equation is solved,the propagation constant can be obtained as the eigen value for a given frequency. Results of the proposed method agaree well with those of high frequency structure simulator（HFSS）.
