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Under the traditional droop control, hybrid energy storage system cannot take advantage of the respective merits of battery and supercapacitor for frequency coordination, which shortens system life. Because of the single‐phase inverter load, the second harmonic current is generated in the front‐stage converter when the output power pulsates at twice the output voltage frequency. This paper proposes a strategy for frequency coordination and second harmonic current suppression based on composite virtual impedance. Under this strategy, the system equivalent output impedance exhibits resistance and inductance in low‐frequency part, dominated by the battery side. The battery reacts slowly to absorb the low‐frequency power fluctuations and provide the energy required by load at steady state. It is capacitive in the high‐frequency range, with the supercapacitor side dominating. The supercapacitor quickly absorbs the high‐frequency part of power fluctuation to suppress the impact of load mutation on DC bus and improve system dynamics. Meanwhile, the strategy realises that the inductor branch impedance is significantly larger than the capacitor branch impedance at double frequency, suppressing the second harmonic current and increasing the system efficiency. Experimentation confirms the effectiveness of the control strategy. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the efficacy of acellular collagen scaffold (ACS) in combination with basic fibroblast growth factor (bFGF) for the repair of traumatic tympanic membrane (TM) perforation in a rat model. Study Design: A prospective controlled animal study in a rat model of traumatic TM perforation. Setting: Tertiary medical center. Subjects and Methods: Sprague-Dawley rats (N = 84) with unilateral traumatic perforation of the right TMs were randomized to receive ACS, bFGF, ACS in combination with bFGF (ACS/bFGF), or nothing (spontaneous healing without any interventions as a control group). The healing outcomes were evaluated by otoscopy, optical coherence tomography, histology, and transmission electron microscopy at 1, 2, and 4 weeks postoperatively. The hearing outcomes were assessed with auditory brainstem response testing. Results: ACS/bFGF resulted in higher perforation closure rates at an earlier stage than spontaneous healing, ACS, and bFGF. Based on histology, optical coherence tomography, and transmission electron microscopy, a trilaminar structure and uniform thickness with mature, densely packed collagen fibers were seen in the ACS/bFGF group. Auditory brainstem response evaluation also showed that ACS/bFGF treatment promoted faster functional hearing recovery as compared with the control group. Conclusions: ACS is an effective TM scaffold and a carrier for bFGF. ACS/bFGF improves the TM closure rate, results in better-reconstructed TMs, and improves hearing. ACS/bFGF serves as a potential substitute for TM perforations in clinical settings. [ABSTRACT FROM AUTHOR]

In this article, we focus on error estimates to smooth solutions of semi-discrete discontinuous Galerkin (DG) methods with quadrature rules for scalar conservation laws. The main techniques we use are energy estimate and Taylor expansion first introduced by Zhang and Shu in (Zhang and Shu, SIAM J Num Anal 42 (2004), 641-666). We show that, with [ABSTRACT FROM AUTHOR]