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In order to reduce the switching frequency involved in the traditional three-level model predictive control utilized for permanent magnet synchronous motors(PMSMs), a model predictive torque control scheme associated with the switching frequency optimization is proposed. Firstly, the reason for higher switching frequency in the three-level drive system is analyzed in depth. Then, the vector screening strategy considering switching state restriction is introduced and the switching frequency constraint is constructed in the cost function, which can effectively reduce the switching frequency as well as decrease the number of candidate vectors. Furthermore, the neutral potential is balanced in terms of the opposite effect of positive and negative redundant small vectors on neutral potential. Finally, the validity of the control strategy is verified by the simulation and experiment. The simulated and experimental results prove that the switching frequency of the proposed control strategy is reduced by nearly half of that in traditional strategy;meanwhile, the fluctuation of neutral potential is eliminated.

In an effort to equalize the quality of teacher resources across all state schools in the compulsory education sector of China and eliminate the school choice phenomenon, the Chinese government has launched a nationwide program of rotating principals and teachers. This study has revealed mixed results to date. While the rotation of teachers has helped to narrow the gap in teacher quality between the low-performing and high-performing schools, the study has revealed some important issues that need to be addressed, such as conflict of goals, ineffective incentives, and rotation for rotation's sake. Whether such a Robin Hood method of "robbing the rich in order to help the poor" can consistently raise the quality of teacher resources and improve the overall quality of education across the whole country remains to be seen.

Aim Methods Results Conclusions The purpose of this study was to determine the risk factors for death in children with influenza‐associated encephalopathy (IAE) in the paediatric intensive care unit (PICU).Forty‐six paediatric patients with IAE admitted to the PICU at shenzhen Children's Hospital between December 2009 and December 2021 were evaluated. Their clinical characteristics were retrospectively analysed.A total of 46 patients were diagnosed with influenza A virus infection and encephalopathy. The cases were concentrated in children <5 years of age (27/46, 58.7%). Twenty‐nine patients (63.0%) survived and 17 patients (37.0%) died, of which 70.6% (12/17) of the patients died within 1 week of hospitalisation. Thirty‐two patients (69.6%) developed neurological symptoms within 1–2 days of fever onset. Common symptoms included fever (45/46, 97.8%), loss of consciousness (39/46, 84.8%), seizures (31/46, 67.4%), cough (19/46, 41.3%), and vomiting (16/46, 34.8%). Multivariate logistic regression analysis indicated that vomiting (odds ratio [OR], 11.005), loss of consciousness (AVPU score: P; OR, 15.871), lymphopenia (OR, 8.964), alanine aminotransferase (>80 IU/L; OR, 32.060) and serum sodium concentration (>145 mmol/L or <135 mmol/L; OR, 16.264) were related to mortality.The mortality in this study population was 37.0%. Children with IAE who have corresponding clinical manifestations and abnormal examination results in PICU should be warned of the high mortality rate. [ABSTRACT FROM AUTHOR]

Since it emerged in the mid-1980s, the school choice phenomenon in China has been the target of severe criticism from all levels of government and the general public. The current nationwide movement of rotating teachers and principals (RTP) is a new attempt to control and eventually eliminate the practice of school choice. Using data from interviews with two education officials and 42 parents, together with relevant government documents, this study applies Hirschman's concept of exit and voice to explore how parents express their dissatisfaction (voice) and exercise (or not) their choice behaviour (exit) in reaction to the government's strategic use of RTP. Findings from this study suggest that RTP and related efforts have had an impact on reshaping parents' perception of the schools and has greatly reduced the parents' school choice behaviour, which is more obvious among second- and third-tier schools than among first-tier schools, indicating that parental desire to send their children to these topmost schools remains strong. Some level of school choice can be expected to exist for the foreseeable future, given China's current exam-driven educational system and the advantages that first-tier schools enjoy, which will maintain and possibly widen the gap between themselves and lower ranked schools. [ABSTRACT FROM AUTHOR]