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Traditional vacuum circuit breaker (CB) equipped with a bistable permanent-magnet (PM) actuator suffers from the disadvantages of having long start-up time and large current peak, and these shortcomings are limiting its applications on synchronization operation and high-voltage switchgear. In this paper, a new drive circuit which can significantly weaken the flux of the holding force with the usage of an auxiliary capacitor is proposed. In the proposed circuit, a negative current is circulated in the respective coil when the PM actuator is ready to switch on or off. Cosimulation which integrates the PM actuator and the circuit is carried out with the Maxwell and Simplorer software. The prototype is tested on the platform in conjunction with a 10-kV PM vacuum CB (VCB) to showcase the success of the proposed flux-weakening control strategy. [ABSTRACT FROM PUBLISHER]

This paper presents a study on decoupling control of a linear and rotary permanent magnet actuator (LRPMA) with linear, rotary and helical movements. Since both linear and rotary motions of the actuator are dependent on both current and voltage, a novel two-directional d\-q transformation is proposed to decouple the inter-relationship between the current and voltage in each coil. The expressions of input power, magnetic field energy, rotary torque, linear force and copper loss are all derived. A MATLAB/Simulink model for helical movement is then setup with hysteresis current control. A practical LRPMA prototype is manufactured and its control system is implemented with a dual digital signal processor. Simulations and experimental measures on the LRPMA prototype are reported to showcase the effectiveness of the control strategy. [ABSTRACT FROM PUBLISHER]

This paper reports a new application of permanent magnet actuator for vacuum contactors. A novel permanent magnet (PM) actuator to drive a vacuum contactor with intrinsically safe and low supply voltage is proposed. PM is mounted on the static iron of the contactor to enhance its holding force and reliability. While only one coil is used to break the vacuum contactor, two series coils are deployed to yield a high magnetomotive force to realize the making operation. The electrical circuit equation, mechanical equation and magnetic field are all coupled in the simulation. A prototype is manufactured and tested to validate and showcase the performance of the contactor which is equipped with the proposed PM actuator. [ABSTRACT FROM AUTHOR]

The arc permanent magnet motor (arc motor) is widely used in large telescope for its high efficiency and high power density. Due to the unique structure, the periodic end torque, cogging torque and flux harmonics will cause certain speed ripples which can affect the performance of the drive system. To solve these problems, the paper proposes a novel model predictive control (MPC) based on extended state observer and iterative learning control, where the MPC is equipped in speed loop and the disturbances estimated by the conventional extended state observer (ESO) are fed forward to the controller to improve the ability of disturbance rejection. A position dependent iterative learning control (ILC) is used to estimate the periodic disturbances at different speeds. The MPC calculates the q axis current reference with the compensation of ESO and ILC, which can have a fast response and disturbance rejection ability for periodic and nonperiodic disturbances. The stability of the proposed method is demonstrated by theoretical analysis. The experimental results validate the effectiveness of the proposed method at different speeds. [ABSTRACT FROM AUTHOR]

This article proposes a novel axial field switched flux memory machine (AF-SFMM) which is analyzed by a combined analytical method. Compared with conventional axial field (AF) permanent magnet (PM) machines having magnets in the rotor side, the AF-SFMM benefits from good heat dissipation, high rotor robustness, and improved power density. Meanwhile, because of the utilization of low coercive force PM materials, the proposed machine can flexibly regulate air-gap flux. This analytical method is characterized by the combination of a quasi-3-D (quasi-3D) finite element method, a magnetomotive force–permeance-based method, and a virtual linear hysteresis model of low coercive force PM. In addition, compared with conventional time-consuming 3-D finite element analysis (FEA), the proposed method can improve the computational efficiency significantly with satisfactory accuracy. This makes the proposed combined analytical method suitable for preliminary sizing determination of AF-SFMM. Meanwhile, the effectiveness of the proposed analytical method is validated by FEA results. [ABSTRACT FROM AUTHOR]

The circumferential and axial widths of permanent magnet (PM) pole and E-shape stator pole of linear rotary motor with interlaced PM poles are very influential to the back electromotive force (EMF) and the flux leakage analysis is complex, which causes difficulty in optimization of the motor structure. One of the key issues in optimization design is to calculate the flux leakage accurately. In this article, the main flux and side flux variation laws of stator pole are derived by analytical method. The flux leakage can be divided into the flux leakage between the PM and the mover, flux leakage on the stator tooth tip, and the flux leakage between the adjacent PM poles and stator pole. The 3-D flux leakage calculation model is built, which is suitable for the calculation of magnetic flux based on different motor operating principles. Then the rotational and rectilinear back EMFs are calculated by analytical method, which are consistent with the results analyzed by 3-D finite element method. [ABSTRACT FROM AUTHOR]

• Propose design method of dc contactor considering multiple influence factors. • Propose an energy-saving control strategy for dc contactor. • A prototype of 600 A/750 V dc contactor is manufactured according to the optimized parameters. In order to meet the requirement of electric vehicle to the high power direct current (dc) contactor, this paper investigates the structural optimization design method of actuator and proposes a novel energy-saving control strategy. The operating principles and structural design processes of electromagnetic actuator are demonstrated in detail. The influences of the electromagnetic parameters including the coil skeleton, the wire diameter and the spring pre-pressure are compared and analyzed and then optimized to obtain the optimal combination by orthogonal test method. A new energy-saving control strategy is proposed by adopting pulse width modulation technology to control the holding current at a smaller value after the movable iron reaches to the closed position. A co-simulation coupling magnetic field, machinery and circuit is carried out with the Maxwell and Circuit Editor software. A prototype of 600 A/750 V dc contactor is manufactured according to the optimized parameters. The experimental results validate the effectiveness of the structural optimization design method and the proposed energy-saving control strategy. [ABSTRACT FROM AUTHOR]

A novel mono-stable permanent magnet actuator (PMA) for high voltage vacuum circuit breaker (VCB) and its optimal design method are proposed in this paper. The proposed PMA is featured with a structure of separated magnetic circuits, which makes the holding part and closing driving part work independently without interference. The application of an auxiliary breaking coil decreases the response time in the initial phase of opening operation, and an external disc spring is adopted to accelerate the opening movement, which makes the PMA meet the fast-breaking requirement of high voltage VCB. As calculating the characteristics of the PMA accurately through numerical simulation is a time-consuming process, a multi-objective optimization (MOO) algorithm based on surrogate modeling technique and adaptive samples adding strategy are proposed to reduce the workload of numerical simulations during optimization. Firstly, initial surrogate models are constructed and evaluated, and then iteratively updated to improve their global approximating abilities. Secondly, according to the approximate MOO results obtained by the global surrogate models, additional samples are added to constantly update the surrogate models to gradually improve the models' local accuracies in optimal solution regions and finally guide the algorithm to the true Pareto front. The efficiency and accuracy of the proposed algorithm are verified by test functions. By applying the optimization strategy to the design of the proposed PMA, a set of satisfying Pareto optimal solutions, which improve the overall performance of the PMA obviously, can be derived at a reasonable computation cost. [ABSTRACT FROM AUTHOR]

• Using a test reclose operation to reduce the impact of permanent short circuit fault. • The characteristics of test current are extracted for fault diagnosis. • The phase-controlled technology is used to control circuit breakers. • An improved fault diagnosis method is proposed to ensure of fault diagnosis accuracy. When a short-circuit fault occurs in a power system, the peak value of the fault current is typically high, causing negative effects, such as insulation aging. The auto-reclose function is effective in reducing the impact of transient faults and has been widely used to improve power supply reliability. In the traditional reclose function, the fault current exists several cycles after reclosing. This is because of the fault diagnosis process, response time of the protective device, and arc duration. To resolve this problem, a new reclose function for distribution networks is proposed in this paper. In the proposed reclose function, a fast making–breaking operation is performed to obtain the test current before closing. The hold-on time of the circuit breaker (CB) is controlled in one cycle using phase-controlled technology. Because of the short duration of test current, a fault diagnosis method considering both the value and distortion degree of test current is proposed to improve the effectiveness of fault diagnosis. The characteristics of test current are obtained theoretically based on an equivalent resistance-inductor-capacitor series circuit. The "making" command is only sent to CBs when a transient fault occurs. The simulation and experimental results show that the proposed function can significantly reduce the influence of the fault current when a permanent short-circuit fault occurs in the power system. [ABSTRACT FROM AUTHOR]

This article proposes an improved tubular single-phase permanent magnet linear oscillation actuator (SP-PMLOA) considering eliminating detent force for direct drive compressor applications. First, the flux tube method and Maxwell stress tensor are used to derive the end force and cogging force formulations based on the magnetic flux leakage of the magnet rings. Then, a novel model with minimum detent force is presented by finite element parametric sweeping. Finally, the electromagnetic performance of the three SP-PMLOAs is compared using 2-D finite element analysis (FEA), whose merits are evaluated, and the thermal distribution of the optimal PMLOA is analyzed using 3-D FEA. The predicted results show that the proposed structure not only can significantly reduce the detent force and the mover axial length but also can increase the thrust force-moving magnet mass ratio. [ABSTRACT FROM AUTHOR]

This paper proposes a metasurface design approach with perforated labyrinthine path coil structure to manipulate the acoustic transmission with inexpensive materials. The medium in the labyrinthine path coils in this design is air, but not limited to air. A systematic approach has been proposed for the unit cell design of acoustic metamaterials with adjustable resonance peak frequencies and bandgap width. The theory demonstrates that the length of pipe segments determines resonance peak frequencies and the cross-sectional area ratio adjusts the bandgap width. The proposed design approach uses an equivalent pipe circuit based analytical model to design the high transmission (high pass) and high reflection (low pass) unit cell. The simulation and experiment has been performed to evaluate the validity of the theory. Although there exists some assumptions in the theory, the theory still has enough accuracy to guide the metasurface design illustrated by the simulation and experiment results. [ABSTRACT FROM AUTHOR]

The hybrid permanent magnet (PM) variable flux memory machine employs high‐ and low‐coercive‐force hybrid PMs to simultaneously obtain a high torque density and regulable PM flux property. The operating trajectories and steady working‐points of this type of machine switch back and forth in multiple regions. To identify operating modes under various PM magnetisation states and speed ranges, this paper proposes a mode recognition and coordinated control method based on probabilistic neural networks (PNNs). A PNN algorithm is trained offline and executed in real‐time to obtain a certain operating mode with the maximum probability of current state. According to the mode recognition result, a coordinated control scheme for applying short‐time pulses or continuous flux‐weakening current in a reasonable manner is presented. The proposed method exhibits an excellent capability in real‐time operating modes identification, hence achieving magnetisation current control of multiple modes easily. Its feasibility and effectiveness are validated by experimental results on a hybrid PM VFMM prototype. [ABSTRACT FROM AUTHOR]

A memory machine (MM) equipped with hybrid permanent magnets (PMs), i.e., NdFeB and low coercive force PMs, exhibits acceptable torque capability at low speeds and high efficiency at high speeds. Previous literatures have addressed that the constant power speed range (CPSR) of MMs can be further extended by online PM flux control and the requirement of the flux-weakening (FW) inverter current can be reduced as well. Nevertheless, how to coordinate the d-axis vector FW and PM magnetization control over a whole operating range in a reasonable manner remains unreported. Therefore, this paper proposes and implements a stepwise magnetization control strategy on a dc-magnetized MM based on the operating characteristics under various PM magnetization states and speed ranges. The configuration, principle, and mathematical model of the investigated machine are introduced first. Then, the proposed control strategy is established by dividing the operating envelop into several FW regions and an appropriate FW control scheme is utilized at each stage. It demonstrates that the CPSR can be effectively extended by simply applying the demagnetizing current pulses in several steps. This simplifies the control efforts considerably without resorting to continuous PM flux control and frequent actions of the switching devices. The effectiveness of the proposed control strategy is verified by experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes an adjustable-speed permanent magnet eddy-current coupling with a non-rotary mechanical flux adjuster (MFA) to regulate the speeds of large pump and fan for energy saving. The slip speed of the proposed coupling can be adjusted by shifting MFA along the axial direction. The structural feature and operation principle of the coupling are illustrated and addressed. A magnetic equivalent circuit model is established for analyzing the electromagnetic characteristics of the coupling efficiently. The air-gap magnetic fields, eddy-current densities, and torque–slip characteristics are investigated under different shifting distances of MFA, which reveals the fairly good torque regulation effects. The torque regulation range reaches to about 90% of the maximum torque, which indicates that the coupling can achieve a large speed regulation range by using the relatively simple approach. [ABSTRACT FROM AUTHOR]

[Display omitted] • The self-assembly of Fe(III) and XG on coal surface was studied. • The layer-by-layer self-assembly multilayers is found on coal particles surface. • The aggregation model of coal slurry with Fe(III) and XG was drawn. Aggregation is an economical and widely existing method to in fine coal particles dewatering, but the effect of cations on the flocculation activity of different bio-flocculant was inconformity. In this work, the aggregation behavior of coal slurry using XG combination Fe3+ was investigated. The adsorption of FeCl 3 ·6H 2 O and XG was investigated via wetting heats, water contact angle, Zeta potential and SEM-EDS testing. The results show that the combination of FeCl 3 ·6H 2 O and XG could build up layer-by-layer self-assembly multilayers on coal particles surface. Further, solution chemistry, FTIR and XPS analyses were performed to detect the adsorption mechanism. The results indicate that Fe(OH) 3(s) covering and coordination reaction of the Fe active sites with the polar groups of XG are the main driving force for the self-assembly. The obtained settling tests results show a great potential of the combination of XG combination Fe3+ in the dewatering of coal slurry. The flocculation dewatering model of coal with FeCl 3 ·6H 2 O and XG was drawn. [ABSTRACT FROM AUTHOR]

Wind power generation has increased rapidly in China over the last decade. In this paper the authors present an extensive survey on the status and development of wind power generation in China. The wind resource distributions in China are presented and assessed, and the 10 GW-scale wind power generation bases are introduced in details. The domestic research status of main components of WP system is then elaborated, followed by an evaluation of the wind power equipment manufacturers. Finally, the outlook for the development of the wind power utilization in China is presented. [ABSTRACT FROM AUTHOR]

Background: Inflammation and obesity are the risk factors for hyperlipidaemia. Nonetheless, research regarding the association between dietary live microbes intake and hyperlipidaemia is lacking. Therefore, this study focused on revealing the relationship between them and mediating roles of inflammation and obesity., Methods: Totally 16,677 subjects were enrolled from the National Health and Nutrition Examination Survey (NHANES) (1999-2010 and 2015-2020). To explore the correlation between live microbes and hyperlipidaemia as well as blood lipid levels, respectively, multiple logistic regression and linear regression were employed. Furthermore, the mediating roles of body mass index (BMI), C-reactive protein (Crp) and their chain effect were explored through mediating analysis., Results: High dietary live microbes intake was the protective factor for hyperlipidaemia. In addition, high dietary live microbes intake exhibited a positive relationship to the high-density lipoprotein cholesterol (HDL-C) among males (β = 2.52, 95% CI: 1.29, 3.76, P < 0.0001) and females (β = 2.22, 95% CI: 1.05, 3.38, P < 0.001), but exhibited a negative correlation with triglyceride (TG) levels in males (β = -7.37, 95% CI: -13.16, -1.59, P = 0.02) and low-density lipoprotein cholesterol (LDL-C) levels in females (β = -2.75, 95% CI: -5.28, -0.21, P = 0.02). Crp, BMI and their chain effect mediated the relationship between live microbes with HDL-C levels. Moreover, BMI and the chain effect mediated the relationship between live microbes with LDL-C levels., Conclusion: Dietary live microbes intake is related to a lower hyperlipidaemia risk. Crp, BMI and their chain effect make a mediating impact on the relationship., (© 2024. The Author(s).)

Aims : Diet can modify the risk of cognitive decline. However, research on the relationship between dietary intake of serine and cognitive decline remains limited and this study aims to reveal the relationship between them. Methods : Data from the National Health and Nutrition Examination Survey (NHANES) 1988-1994 ( n = 1837) were used to explore the relationship between dietary intakes of serine and cognitive function through quantile multiple linear analysis and restricted cubic splines (RCS) regression. We also investigated 9 food groups for serine intake according to the USDA food code to determine which food sources of serine are beneficial for cognitive function. Results : The top three serine intakes were attributed to meat/poultry/fish, grain products, and milk or milk products. Multivariable linear regression analysis showed that a significant negative linear trend was observed between serine intake and SDLT. RCS results showed a non-linear relationship between serine intake and SDLT or SDST. Among the 9 food group intakes, milk or milk products sourced serine intake was good for memory ability. Conclusion : serine, particularly serine from milk or milk products, has a beneficial impact on memory ability in adults.

Background: Osteoporosis (OP) is a progressive metabolic disorder that is difficult to cure clinically. The molecular mechanisms of OP urgently need to be further examined. This study was designed to explore the potential function of circ&#95;0027885 during osteogenic differentiation, as well as the systematic interactions among circ&#95;0027885, miR-203-3p and runt-related transcription factor 2 (RUNX2)., Methods: Relative levels of circ&#95;0027885, miR-203-3p and RUNX2 were analyzed with RT-qPCR and western blotting. Alizarin red staining was performed to detect the mineralization ability under the control of circ&#95;0027885 and miR-203-3p. Dual-luciferase reporter gene assay was conducted to examine the combination among circ&#95;0027885, miR-203-3p and RUNX2., Results: Our research demonstrated that circ&#95;0027885 was significantly increased during hBMSCs differentiation. Overexpression of circ&#95;0027885 notably facilitated osteogenic differentiation and upregulated RUNX2 expression, while knockdown of circ&#95;0027885 reversed the above results. Through prediction on bioinformatics analysis, miR-203-3p was the target binding circ&#95;0027885, and RUNX2 was the potential target of miR-203-3p. Subsequently, these changes induced by the overexpression of circ&#95;0027885 were reversed upon addition of miR-203-3p mimic., Conclusions: Circ&#95;0027885 could sponge miR-203-3p to regulate RUNX2 expression and alleviate osteoporosis progression., (© 2023. The Author(s).)

Functional integrity of the regenerated tissues requires not only structural integrity but also vascularization and innervation. We previously demonstrated that the three-dimensional (3D) reconstructed eccrine sweat glands had similar structures as those of the native ones did, but whether the 3D reconstructed glands possessing vascularization and innervation was still unknown. In the study, Matrigel-embedded eccrine sweat gland cells were implanted under the inguinal skin. Ten weeks post-implantation, the vascularization, and innervation in the 10-week reconstructed eccrine sweat glands and native human eccrine sweat glands were detected by immunofluorescence staining. The results showed that the fluorescent signals of general neuronal marker protein gene product 9.5, adrenergic nerve fiber marker tyrosine hydroxylase, and cholinergic nerve fiber markers acetylcholinesterase and vasoactive intestinal peptide embraced the 3D reconstructed glands in circular patterns, as the signals appeared in native eccrine sweat glands. There were many CD31- and von Willebrand factor-positive vessels growing into the plugs. We demonstrated that the 3D reconstructed eccrine sweat glands were nourished by blood vessels, and we for the first time demonstrated that the engineering sweat glands were innervated by both cholinergic and adrenergic fibers. In conclusion, the 3D reconstructed eccrine sweat glands may have functions as the native ones do.