Design of a weak bioelectric signal acquisition circuit

A surface electromyography(sEMG)signal acquisition circuit based on high-order filtering is designed.We use a two-stage adjustable amplifier and a high-order Sallen-Key bandpass filter to solve the problems of non-adjustable amplification gain and low filtering order in traditional acquisition circuits.The experimental results show that the designed sEMG signal acquisition device can eliminate power frequency interference effectively,the stopband drop of the filtering part reaches approximately-100 dB/dec,which can effectively extract useful signals between 20-500 Hz,and the amplification gain reaches 60 dB.

Mathematical model analysis of new-type magnetic integrated CRT considering magnetic leakage

A novel magnetic integrated controllable reactor of transformer type(CRT)has the advantages of simple structure,flexible assembly,convenient maintenance and practicability.To analyze its operation characteristics accurately,we establish corresponding equivalent mathematical model considering magnetic leakage based on magnetic circuit and circuit dualistic transformation method.The distribution of magnetic leakage field of each winding is analyzed qualitatively,and the analytical calculation formulas of magnetizing inductance and leakage inductance of each winding are derived.Based on this,the analytical calculation formulas of short-circuit impedance and winding current of CRT under different working conditions are derived.The field-circuit coupling finite element model of the magnetic integrated CRT is established to simulate the current of each winding under different working conditions.The results show that the analytical calculation results of each winding current have good consistency with the finite element calculation results,indicating the validity of CRT equivalent mathematical model and correctness of the analytical formulas of leakage inductance,short-circuit impedance and winding current of CRT.The working winding current of CRT is increasing gradually with the operation of control winding in turn to realise the transition of CRT compensation capacity from zero to a rated value.

滨水绿道在城市景观格局中的建设研究——以宝鸡市渭河滨水绿道为例

在“全域旅游”和“绿色出行”的推动下,绿道越来越成为当前城市公共开放空间建设的新浪潮。城市滨水区作为城市中最具活力的空间连接着城市水域和陆域空间,是城市发展不可忽略的重点建设区域。以宝鸡市渭河滨水绿道为例,探索城市滨水区融合绿道建设的新方向,对城市滨水绿道在城市整体景观建设格局中的作用和地位进行研究,为城市滨水区的建设提供方向指引。