此文把通常进位制的概念扩张成复数进位，且由复数进位给出了一类纯粹由数学定义引出的分形。
We first extend the concept of ordinary number system, and study the complex number numeration. Then we give an example of fractal by the complex number numeration.
从桩基础的研究现状引入桶形基础的研究现状，进而引出桩-桶基础的结构概念及相关研究。
From the research actuality of pile to the bucket foundation's, then the pile-bucket foundation structure concept and the correlated research is educed.
从双口网络的Z参数、Y参数出发，推导了星形、三角形网络转换在正弦稳态电路中的转换公式，引出其应用条件。
In this paper, starting from the conversion of Z parameters and Y parameters of two-port parameters, we deduce the formulas of wye-delta network transformation in sinusoidal steady-state.
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