Equivalent series system to model a multiple friction pendulum system with numerous sliding interfaces for seismic analyses

Current structural analysis software programs offer few if any applicable device-specifi c hysteresis rules or nonlinear elements to simulate the precise mechanical behavior of a multiple friction pendulum system(MFPS) with numerous sliding interfaces.Based on the concept of subsystems,an equivalent series system that adopts existing nonlinear elements with parameters systematically calculated and mathematically proven through rigorous derivations is proposed.The aim is to simulate the characteristics of sliding motions for an MFPS isolation system with numerous concave sliding interfaces without prior knowledge of detailed information on the mobilized forces at various sliding stages.An MFPS with numerous concave sliding interfaces and one articulated or rigid slider located between these interfaces is divided into two subsystems: the fi rst represents the concave sliding interfaces above the slider,and the second represents those below the slider.The equivalent series system for the entire system is then obtained by connecting those for each subsystem in series.The equivalent series system is validated by comparing numerical results for an MFPS with four sliding interfaces obtained from the proposed method with those from a previous study by Fenz and Constantinou.Furthermore,these numerical results demonstrate that an MFPS isolator with numerous concave sliding interfaces,which may have any number of sliding interfaces,is a good isolation device to protect structures from earthquake damage through appropriate designs with controllable mechanisms.

The Equivalent Parameters for the Narrow Series Slot on a Sectoral Waveguide

The exact and approximate expressions for the field components of the TE modes in a sectoral waveguide are presented. Using the equivalence principle, the electric field distribution on the aperture surfaces of a narrow transverse slot cut in the curved broad wall of a sectoral waveguide is solved by the moment method (Galerkin's method). lmportant results such as the scattering parameter, the normalized equivalent series impedance, the resonant resistance and resonant length are studied.

Design of a fast-transient and high-stabilized GPS low dropout regulator

A high stabilized low dropout(LDO) voltage regulator fabricated for GPS radio frequency(RF) chip in SMIC 0.18μm CMOS technology is presented.The LDO mainly consists of bandgap reference,error amplifier,resistive feedback network and AC current path.A fast current path is added to improve the performance of LDO's transient response.Equivalent series resistance(ESR)compensation and internal Miller compensation are used to constitute the frequency compensation.The measurement results of the transient response of the output voltage show that it can recover within 2μs with less than 120 mV ripple when the load current is changed from 0 to 100 mA.The total quiescent current of LDO and bandgap reference(without load) is 260 μA.

Impedance spectra of different capacitor technologies

This paper reviews the interpretation of impedance and capacitance spectra for different capacitor technologies and discusses how basic electrical characteristics can be inferred from them.The basis of the interpretation is the equivalent circuit for capacitors.It is demonstrated how the model parameters,such as capacitance and equivalent series resistance,can be extracted from the measured spectra.The aspects of measurement accuracy are exemplarily discussed on the measured spectra.