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Active magnetic bearings (AMBs) commonly use pulse-width modulation to reduce analogous hardware and manufacturing costs, but they experience sensing process, sensing accuracy and stability problems. To address these issues, a synchronous sampling-based direct current estimation (SS-DCE) method is proposed herein with a bistate switching power amplifier. First-considering the reluctance evolution mechanism of AMBs-a coupling relation mathematical model between rotor displacement and voltage/current is presented to acquire the rotor position from the working coil current alone. Then-assuming that the switching current was an approximately triangular signal-a DCE for the rotor position was established based on the estimation inductance of the charging/discharging phase. Finally-to decrease the phase shift caused by the self-sensing filters and position estimation algorithms-the SS-DCE method was introduced to conduct precise position detection for rotors with high velocities. The simulation and experimental results indicated that the proposed method could improve the sensing accuracy and stability. Compared to other AMB position estimation methods, the simple linearity of the SS-DCE method was greatly improved and could be controlled below 4%. Evaluation using frequency response analysis showed that the SS-DCE method had excellent dynamic accuracy and could perform at a higher phase margin, especially for the uprising/landing transient state. Moreover, there was a phase margin of 158° at the natural frequency of 19.26 HZ, and the peak sensitivity in the 50-250 µm range reached 10.7 dB.
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INTRODUCTION: With the widespread spread of novel coronavirus pneumonia, more and more countries have been affected. Some research reports have shown that traditional Chinese medicine has a significant effect on COVID-19 infection, and the treatment of traditional Chinese medicine is used in some special people, such as children. At present, there is a lack of high-quality systematic reviews on the safety and efficacy of using Chinese medicine to treat children with novel coronavirus pneumonia. MATERIALS AND METHODS: We will search Cochran library, MEDLINE, EMBASE, China National Knowledge Infrastructure Database (CNKI), China Biomedical Database (CBM), VIP Database (VIP), and Wanfang database for research. This study includes randomized controlled trials (RCTs) and non-RCTs, and uses the Cochrane systematic review to review the safety and efficacy of traditional Chinese medicine in preventing and treating children with novel coronavirus pneumonia. RCT research tools and quantitative research quality assessment tools for non-randomized studies will be used to assess the risk of bias in studies included in the systematic review. We will use Revman 5.3 software for meta-analysis, the main result is odds ratio, and then a subgroup analysis will be performed based on the age, intervention degree, and disease severity of the patients reviewed. ETHICS AND DISSEMINATION: This systematic review protocol is designed to provide evidence regarding the effectiveness and safety of traditional Chinese medicine for the treatment of children with COVID-19, such evidence may be useful and important for clinical treatment decisions. The results should be disseminated through publication in a peer-reviewed journal. Since the data and results used in the systematic review will be extracted exclusively from published studies, approval from an ethics committee will not be required. REGISTRATION INFORMATION: PROSPERO CRD42020179150.
Assuntos
Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Medicina Tradicional Chinesa/métodos , Pneumonia Viral/tratamento farmacológico , Adolescente , COVID-19 , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pandemias , Projetos de Pesquisa , SARS-CoV-2 , Revisões Sistemáticas como Assunto , Resultado do Tratamento , Tratamento Farmacológico da COVID-19RESUMO
The paper presents a novel fetal heart rate (FHR) detecting system which is a fuzzy counter using the auto-correlation and fuzzy mathematic algorithm. This system is able to deal with the increase and decrease phenomena of FHR, caused by the various interference and noises. It has a higher detection level than ever and a better robust system based on the DSP.