Expanding Limit of Minimum Sampling Time Using Auxiliary Vectors for PMSM Drives with Single DC-Link Current Sensor

Phase current reconstruction (PCR) strategy can improve the fault tolerance of permanent magnet synchronous motor (PMSM) drives. The PCR precision is largely affected by the unmeasurable zones and time-sharing sampling errors. The upper limit (Tlimit) of PCR allowable range can reflect the requirement of different PCR methods for the minimum sampling time (Tmin). With a longer Tlimit, there is sufficient time for sampling, even if Tlimit is halved due to the symmetrical waveform. Therefore, the extension of Tlimit is the key to eliminate the unmeasurable zones and time-sharing sampling errors. In this paper, a method to increase Tlimit is proposed, which introduces the suitable auxiliary vectors (AVs) in different regions to extend the duration time of the sampling vectors. With the help of a longer Tlimit (12.5%Ts), its possible to eliminate all the unmeasurable zones and time-sharing sampling errors, relieve the pressure on the hardware of current loop, improve the sampling accuracy, and facilitate the reliable operation of the drive. Besides, the switching action times of IGBTs can be reduced by about one-third in the high modulation area. The proposed method is finally proved to accurately reconstruct the phase currents by the experimental results on the PMSM prototype

Exploration of Primary General Medical Care Quality Management：a Case Study of Shanghai General Practice Clinical Quality Control Center

The general medical care quality management system plays an essential and key role in assuring the quality of general medical care and patient safety in primary care settings. There are no unified criteria and methods for assessing the primary general medical care quality, and rare relevant quality improvement research and practical explorations in China.We reviewed the primary general medical care quality management nationwide, and highlighted the problems, then particularly detailed the three-year (2018—2020) implementation status and achievements of Shanghai, in which the primary general medical care quality was managed by Shanghai General Practice Clinical Quality Control Center (hereinafter referred to as Quality Control Center) in an exploratory way. And the management actions taken by the quality control center were as follows: defining the organizational objectives and tasks; developing the organizational framework and allocating workers; establishing municipal-and district-level organizational networks and operational systems for primary general medical care quality control; developing the inspection indicators for assuring primary general medical care quality; conducting an annual investigation of the general medical care in each of the primary care settings in Shanghai, and providing targeted guidance as well as supervision. The actions of the Quality Control Center provide strong support for quality improvement and safety assurance of primary general medical care. And the practical explorations of the Quality Control Center could be a reference for improving primary general medical care quality management nationwide. To improve the primary general medical care quality management at the naitonal level, which is still in its early phase, we put forward four recommendations: improving the development of the organization system, developing a scientific system for assessing the primary general medical care quality, comprehensively and dynamically carrying out quality controlsupervision regarding primary general medical care, and strengthening the quality controlsupervision

Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at √sNN = 5.02 TeV with the LHCb detector

Flow harmonic coefficients, v n , which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02 TeV . The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features

Research on the Coupling and Coordination of Systems of Citizenization, Regional Economy, and Public Service in China from the Perspective of Sustainable Development

Based on the perspective of sustainable development, this paper introduces the circular economy dimension into the economic system, the ecological environmental protection dimension into the public service system, and constructs index evaluation systems for citizenization, regional economy, and public service, respectively. Then, the paper establishes a coupling coordination model to study the mutual relationship between citizenization, regional economy, and public service at provincial levels, so as to promote the sustainable development of population, economic society, and resource environment. The main research conclusions are as follows: (1) the level of citizenization is generally low, and the dimensions of income and social security are weak; (2) the development trend of circular economy in the eastern regions is better than that in other regions; (3) the “Citizenization, Regional Economy, Public Service” System has an overall low coupling and coordination degree and it shows a trend of “high in the east and low in the west”; (4) the contradictory characteristics between the systems vary greatly by province. Most of the provinces’ systems of the regional economy and public service lag behind their citizenization and some developed provinces have a lag in their citizenization systems. In order to promote a high-quality coordinated development between the systems of citizenization, regional economy, and public service, a sustainable development path that adapts to local conditions must be sought. It should focus on improving the social security level of rural-to-urban migrants, establishing a circular economy, and strengthening the construction of an ecological environment

Research on the Coupling and Coordination of Systems of Citizenization, Regional Economy, and Public Service in China from the Perspective of Sustainable Development

Based on the perspective of sustainable development, this paper introduces the circular economy dimension into the economic system, the ecological environmental protection dimension into the public service system, and constructs index evaluation systems for citizenization, regional economy, and public service, respectively. Then, the paper establishes a coupling coordination model to study the mutual relationship between citizenization, regional economy, and public service at provincial levels, so as to promote the sustainable development of population, economic society, and resource environment. The main research conclusions are as follows: (1) the level of citizenization is generally low, and the dimensions of income and social security are weak; (2) the development trend of circular economy in the eastern regions is better than that in other regions; (3) the “Citizenization, Regional Economy, Public Service” System has an overall low coupling and coordination degree and it shows a trend of “high in the east and low in the west”; (4) the contradictory characteristics between the systems vary greatly by province. Most of the provinces’ systems of the regional economy and public service lag behind their citizenization and some developed provinces have a lag in their citizenization systems. In order to promote a high-quality coordinated development between the systems of citizenization, regional economy, and public service, a sustainable development path that adapts to local conditions must be sought. It should focus on improving the social security level of rural-to-urban migrants, establishing a circular economy, and strengthening the construction of an ecological environment

A Modified QuEChERS Method for Determination of Pyrethroid Residues in Traditional Chinese Medicine Oral Liquids by High-Performance Liquid Chromatography

Pyrethroid residues in traditional Chinese medicines have been a serious threat to the health and treatment of patients. However, because of the matrix complexity of traditional Chinese medicine, the detection of pyrethroid residues remains a challenge. Therefore, we developed a QuEChERS method coupled with high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of pyrethroid pesticides in three kinds of traditional Chinese medicine oral liquid preparations, and we investigated and optimized the extraction conditions. The matrix effect was estimated in the organic solvent and the actual samples by comparing the slopes of calibration curves, and the results showed that the matrix effect is not significant when using the modified QuEChERS method. The pyrethroid pesticides could be completely separated in 30 min. The linear correlation coefficients were more than 0.999, and the recoveries of all the pyrethroid pesticides ranged from 87.2% to 104.8%. The intra-day precisions (n = 5) were 2.44–4.62%, and the inter-day precisions (n = 5) were 1.06–3.02%. Moreover, the limits of detection were in the range of 0.007–0.018 ng mL−1, while the limits of quantitation were in the range of 0.022–0.057 ng mL−1. This simple, low-cost, and highly sensitive analytical method can be a potential tool for the analysis of pyrethroid residues in traditional Chinese medicine oral liquid preparations

Synthesis of Metallic Nanocrystals: From Noble Metals to Base Metals

Metallic nanocrystals exhibit superior properties to their bulk counterparts because of the reduced sizes, diverse morphologies, and controllable exposed crystal facets. Therefore, the fabrication of metal nanocrystals and the adjustment of their properties for different applications have attracted wide attention. One of the typical examples is the fabrication of nanocrystals encased with high-index facets, and research on their magnified catalytic activities and selections. Great accomplishment has been achieved within the field of noble metals such as Pd, Pt, Ag, and Au. However, it remains challenging in the fabrication of base metal nanocrystals such as Ni, Cu, and Co with various structures, shapes, and sizes. In this paper, the synthesis of metal nanocrystals is reviewed. An introduction is briefly given to the metal nanocrystals and the importance of synthesis, and then commonly used synthesis methods for metallic nanocrystals are summarized, followed by specific examples of metal nanocrystals including noble metals, alloys, and base metals. The synthesis of base metal nanocrystals is far from satisfactory compared to the tremendous success achieved in noble metals. Afterwards, we present a discussion on specific synthesis methods suitable for base metals, including seed-mediated growth, ligand control, oriented attachment, chemical etching, and Oswald ripening, based on the comprehensive consideration of thermodynamics, kinetics, and physical restrictions. At the end, conclusions are drawn through the prospect of the future development direction