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Due to the magnetic domain movement and energy change under magnetic field and stress applied, the macroscopic magnetic properties and magnetostriction properties of non-oriented (NO) silicon steel are influenced. To present this effect of the magnetic domains' motion mechanism, a stress-dependent magnetostriction must be modeled. This paper proposes an improved stress-dependent magnetostriction model (I-SDM model) for NO silicon steel based on a simplified multi-scale model. Firstly, the stress-dependent expression of the anhysteretic magnetization, obtained by assuming a six-domain structure and considering the volume fraction of magnetic domain energy, is introduced into the inverse Jiles–Atherton (JA) model. In this way, the stress-dependent hysteresis model is constructed. Then, coupling with the improved quadratic domain rotation model that considers pinning effects, the I-SDM model for NO silicon steel is built. Finally, with the parameters obtained from experimental results, the proposed model under varying stresses is simulated and compared with other models. It shows that the proposed model has the highest simulated accuracy for both λ-H loop and λ-B loop with stress applied. [ABSTRACT FROM AUTHOR]

This paper proposed an improved magnetostriction model for correlation of anisotropy in non-oriented (NO) silicon steel based on the free energy, which considers stress-induced and magnetocrystalline anisotropy. Firstly, the free energy model, which includes stress-induced anisotropy energy, the energy of magnetic field, and the anisotropic energy of magnetic crystals, is incorporated into the anhysteretic magnetization parameter Man. Then, to obtain the magnetic field and proposed model parameters related to stress-induced and magnetocrystalline anisotropy, the magnetostrictive strain loops at different magnetization directions of NO silicon steel are measured. Finally, based on the parameters obtained from experimental data of the proposed model, magnetostrictive strain loops under varying magnetization directions are simulated. This improved magnetostriction model can be applied to the calculation of the vector magnetostriction of the motor core. [ABSTRACT FROM AUTHOR]

Global optimization algorithms are widely used to effectively suppress the torque ripple in switched reluctance motors (SRMs). In this paper, an improved velocity-controllable particle swarm optimization algorithm (VCPSO) is proposed to optimize the turn-off angle of an SRM under the current chopping control (CCC) method. In addition, the performances of three global optimization algorithms are compared and analyzed. The specific steps are outlined as follows. First, the static non-linear inductance–current–position and torque–current–position curves of the SRM are obtained through finite-element calculations, and a non-linear model of the SRM is established on this basis. Second, the turn-off angle optimization method based on the VCPSO is proposed. Finally, the performances of the simulated annealing algorithm (SA), the genetic algorithm (GA), and the proposed algorithm are compared and analyzed in terms of torque ripple suppression. The obtained results show that the proposed VCPSO has the advantages of a low number of iterations, low torque ripple, and small peak current in the torque ripple reduction issue of the SRM. [ABSTRACT FROM AUTHOR]

The amorphous alloy used in a switched reluctance motor core can greatly improve the efficiency of the motor. However, its large magnetostrictive coefficient and strong stress sensitivity (i.e., inverse-magnetostriction effect) increase the core vibration and limit the precise control capability of the electrical signals. A vibration reduction method based on the inverse-magnetostriction effect is proposed to control the electromagnetic vibration of a switched reluctance motor with amorphous alloy cores (SRMA). First, a nonlinear magnetostriction and inverse-magnetostriction effect model (NMIE model) of an amorphous alloy and the compressive stress applied structure for the stator teeth are proposed. Then, considering the influence of static compressive stress and dynamic electromagnetic stress on the magnetic properties of the core material, a two-way dynamic electromagnetic force coupling model of the SRMA is constructed and solved. Finally, the vibration characteristics of the SRMA core are calculated. The obtained results show that the radial electromagnetic stress of the improved structure is reduced by 33.6%, which verifies the feasibility of the proposed vibration reduction method. [ABSTRACT FROM AUTHOR]

Magnetically controlled reactors (MCRs) are widely used as reactive power compensation equipment owing to their favorable properties of smoothly adjusting their inductance value through dc bias. However, the dc bias and the rotational magnetization at corner and T-joint areas make the cores of MCRs saturated, resulting in high magnetostriction and vibration. Thus, the electromagnetic vibration analysis of MCRs must consider the vector hysteretic magnetostriction effect. In this article, a vector hysteretic magnetostriction model of silicon steel is proposed by combining the quadratic domain rotation model with the vector inverse Jiles–Atherton model firstly. Then, based on the measured magnetization and magnetostrictive characteristics curves of silicon steel, the model’s parameters are optimized by velocity controllable particle swarm optimization (VCPSO). Finally, the vector hysteretic magnetostriction model is combined with the finite element method (FEM) to simulate the vector vibration characteristics of MCR under dc bias. The simulation results show that the vector property of electromagnetic vibration and magnetic field at the T-joint area is higher than that at other areas. And the MCR vibration test results are consistent with the simulation results, which verify the accuracy of the proposed model in simulating electromagnetic vibration. [ABSTRACT FROM AUTHOR]

The traditional torque sharing function (TSF) strategy can lead to large torque ripple and copper consumption in switched reluctance motors (SRMs) due to the limitation of the voltage in the phase change interval. In this paper, an improvement scheme is proposed to address this problem. First, a segmented non-linear correction TSF (SN-TSF) is proposed. Then with the torque ripple and copper consumption of the SRM as optimization objectives, the proposed SN-TSF values are optimized using the velocity control particle swarm optimization (VCPSO) algorithm based on the particle velocity–boundary relationship. The optimal parameters are used to obtain the optimal SN-TSF curves with different loading torques and speeds. Experimental results show that the proposed SN-TSF strategy reduces the torque ripple by 40.17% and 66.5%, and the peak phase currents by 5.058 A and 5.371 A under two different operating conditions, which demonstrates the effectiveness of this strategy. [ABSTRACT FROM AUTHOR]

The grains of oriented W-type hexaferrite BaNi 2 Gd x Fe 16-x O 27 (BaW) where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 grew uniformly along their c -axis perpendicular to the sample plane, which meant high remanence ratio of BaW. When Gd3+ substitution content was x = 0.0, the corresponding remanence ratio reached as high as 0.90. When x = 0.2, the oriented BaW simultaneously possessed high saturation magnetization (M s = 58.36 emu/g), high coercivity (H c = 1527 Oe), high remanence ratio (M r /M s = 0.85), relatively low magnetocrystalline anisotropy field (H a = 10,253 Oe) and low ferromagnetic resonance linewidth (Δ H = 624 Oe). These characteristics indicated the material was suitable for the design of self-biased circulator operated at K band. Based on the BaW material, self-biased double Y-junction microstrip circulator was designed and realized well circulatory function at K band. [ABSTRACT FROM AUTHOR]

To obtain the deformation characteristic of silicon steel with yoke clamping applied under an alternating magnetic field, a stress-dependent magnetostriction model of silicon steel must be constructed. Due to the magnetic domain's rotation and the magnetic domain wall movement with stress applied, the material's magnetostrictive deformation will reverse and saturate in both magnitude and direction. Therefore, the saturated magnetic domain wall movement effect must be considered in the stress-dependent magnetostriction model. Firstly, a hysteresis stress-dependent magnetostriction model based on the Jiles-Atherton (J-A) model and Zheng-Liu (Z-L) model is proposed. Then, the magnetostrictive deformation curves of the non-oriented silicon steel with external stresses are measured. The magnetic field and deformation parameters that control the saturated magnetic domain wall movement are extracted and applied to the model. Finally, the magnetostrictive loops with the magnetic field under varying stress are obtained based on the proposed model. The proposed model's effectiveness and accuracy are verified by comparing the measurement results with the simulation results. [ABSTRACT FROM AUTHOR]

The magnetic properties of electrical steel sheets are strongly affected by the Multi-Physics Factors (MPF), such as bending stress, working temperature, and magnetization patterns. To investigate the complex magnetic properties of the material under MPF magnetizing conditions, a magnetic property measurement system is first developed, considering the effect of bending stress, temperature loading, and non-sinusoidal magnetization waveforms. Then, the magnetic and the loss properties of Grain-Oriented (GO) electrical steels under MPF magnetizing conditions are measured and discussed. Obtained results showed that bending stress and non-sinusoidal magnetization waveforms are positively correlated with the loss properties of electrical steel sheets, and elevated temperatures can mitigate the effects of bending stress and harmonics on magnetic properties and losses. [ABSTRACT FROM AUTHOR]

For tackling the problem of large errors in simulating the static inner symmetrical minor hysteresis loops through the Simplified Landau-Lifshitz-Gilbert (S-LLG) equation, a modification by improving the grain structure arrangement and introducing additional hysteresis energy function is proposed. With the proposed model, only a unified set of parameters identified by four static hysteresis loops is needed to predict hysteresis loops under arbitrarily different magnetic flux density levels. To verify the global simulation capability of the proposed model, the simulation results of hysteresis loops are compared with the measured data of a grain-oriented (GO) steel. The obtained results show that the model has good simulation ability for hysteresis loops under different magnetic flux densities for both sinusoidal and harmonic excitation conditions. [ABSTRACT FROM AUTHOR]

Due to lacking the measurement results of magnetic properties under rotational magnetization, the application of nanocrystalline alloys for high-power system energy conservation has been limited. In this paper, a high-frequency rotational magnetic property testing system is first introduced. Base on the testing system, the rotating loci of the vector magnetic flux density B and the vector magnetic field strength H are measured. Finally, the rotational core loss and anisotropy of nanocrystalline alloys are discussed and analyzed. [ABSTRACT FROM AUTHOR]

Inverter-fed induction motors generate large vibration and noise because of the Maxwell electromagnetic stress between stator and rotor, magnetostrictive stress of silicon steel and the harmonics in load current. On the vibration reduction study of motor cores, many researchers kept their eyes on control strategy. However, they did not compute stress of inverter-fed induction motor under sinusoidal and harmonic excitations. The nonoriented silicon steel in motor cores shows remarkably anisotropic magnetization and magnetostrictive properties under sinusoidal and harmonic excitations. Thus, in order to compute motor stress accurately, anisotropic magnetic properties must be considered. First, anisotropic property of silicon steel under sinusoidal and harmonic excitations is tested to support the stress computation. Then, an electromagneto-mechanical coupled model for motors considering anisotropic magnetization and magnetostrictive properties is proposed and stress distribution of motor cores is calculated. Finally, the frequency spectrum of the stress is analyzed to provide the theoretical basis for further research of inverter-fed induction motor vibration and noise reduction. [ABSTRACT FROM AUTHOR]

To provide technique references for vibration reduction of magnetically controlled reactors (MCRs), stress, which is the inherent reason of vibration and noise, should be investigated. Stresses in reactor cores are produced due to the magnetostriction deformation of silicon steel and electromagnetic force between the core discs. So far, stress analysis on reactor cores was based on one-way coupled numerical method, which did not consider the influence of the stress on magnetic properties of the core material. Thus, multi-group magnetization and magnetostriction characteristics curves of silicon steel under different tensile stresses are measured firstly to support the computation. From the experiment results, it can be seen that magnetic properties of silicon steel change with stress. Then an electromagneto-mechanical two-way coupled numerical model for MCRs considering magnetostrictive effect and electromagnetic force effect is proposed. Stress distribution of MCR cores under the combination excitation of the sinusoidal wave current and different direct currents are calculated. From the computed results, it can be seen that a larger direct current has greater influence on MCRs vibration, which provides a theory basis for further analysis of vibration and noise reduction. [ABSTRACT FROM AUTHOR]

To clarify the mechanism of the magnetic properties deterioration and the increasing loss of the Grain-Oriented (GO) electrical steel wound cores under serving conditions, the effect of the bending stress in a wide frequency range should be thoroughly investigated. In this paper, a magnetic properties measuring system for GO electrical steel under different bending stress from 50 Hz to 1000 Hz is proposed. To ensure the accuracy and reproductivity of the measurements, the waveform of magnetic flux densities should be controlled to be sinusoidal. However, the bending stress aggravates the material's nonlinear properties, making waveform control very difficult. To solve this problem, a frequency-domain adaptive dual-loop feedback control algorithm is developed. Obtained results show that the proposed method has a good effect on waveform control under bending stress, and the loss of the material under different magnetizing conditions is then analyzed. [ABSTRACT FROM AUTHOR]

To simplify the circuit design and control complexity, a wireless charging system with a switchable hybrid topology based on an integrated coil structure is proposed in this paper. Constant current (CC) and constant voltage (CV) outputs under zero phase angle (ZPA) conditions can be achieved at a fixed frequency by simply throwing the compensation element at the receiver. Firstly, the system is modeled using mutual coupling theory, and the parameter configuration conditions for implementing CC or CV outputs under ZPA conditions are analyzed. Then, according to the obtained parameter configuration conditions, the parameters of the switchable hybrid topology are designed. Finally, an experimental prototype with 72 V charging voltage and 4 A charging current is implemented to validate the proposal. The experimental results agree well with the theoretical analysis. [ABSTRACT FROM AUTHOR]

Based on the consideration of the magnetic domain motion under different magnetization levels, an improved J-A model with variable parameters is proposed to solve the problem of significant errors in the process of calculating the inner symmetric small loops. The proposed method introduces a variable scale parameter v(B) to correct the irreversible magnetization component of the J-A model. Meanwhile, based on the magnetic domain theory, a method with variable pinning parameter k(B) and a variable domain wall bending parameter c(B) is proposed. By comparing the measured data of B30P105 Grain-Oriented (GO) silicon steel, the calculation error for each magnetization level of the model is within 7%, which means that the global hysteresis properties of GO silicon steel can be well reproduced. [ABSTRACT FROM AUTHOR]

The inversed Preisach hysteresis model is widely used to realize the rapid coupling of hysteresis characteristics of core materials in finite element analysis. However, the small major hysteresis loop is difficult to be accurately simulated. In this paper, an improved inversed Preisach model based on an improved parametric distribution function is proposed. By analyzing the magnetic remanence, the waveform factor is coupled with the parametric distribution function, and the identification of the small major hysteresis loop is strengthened. The distribution function parameters can be found from the limit hysteresis loop through the optimization algorithm. In the numerical calculation process of the model, the amplitude correction coefficient in the discrete formula is extracted by the basic magnetization curve. Compared with the previous method, this method simulates the limit hysteresis loop well and has higher simulation accuracy for the small major hysteresis loops. [ABSTRACT FROM AUTHOR]

To accurately predict the eddy current loss of silicon steel laminations over broadband frequency range, an improved parametric magneto dynamic model (IPMD) is proposed in this paper. According to the nonuniform distribution of magnetic field in the cross-section of the silicon steel lamination under high-frequency magnetization, the analysis area of the lamination is divided into several slices by nonlinear segmentation, wherein each slice the magnetic field distribution is regarded as uniform. Meanwhile, to accelerate the calculation speed of the IPMD model, the relationship between skin depth and slice number is deduced and verified. Furthermore, the Tellinen (TLN) hysteresis model is used when implementing the IPMD model to further increase the accuracy of eddy current loss calculation. [ABSTRACT FROM AUTHOR]

The Preisach model is widely used to simulate the magnetic performance of transformers and motors in industrial applications. However, its parameter identification problem is still a complicated task. This paper proposed a new parameter identification method based on the velocity-controlled particle swarm optimization (VCPSO) algorithm combined with the closed-form Everett function. Firstly, the Preisach model is built through the closed-form Everett function, which gives an explicit form Preisach model. Secondly, the Preisach model's parameter identification is realized by using the VCPSO algorithm, which only needs the limiting static hysteresis loop of the material. During the optimization process, the particle velocity is automatically adjusted to avoid falling into the optimal local solution. Finally, the obtained results are compared with the experimental hysteresis loop of the B30P150 silicon steel. [ABSTRACT FROM AUTHOR]

Background: Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3) has been implicated in the progression of esophageal cancer (EC). However, the specific mechanism of the involvement of MEG3 in EC development in relation to the regulation of immune escape remains uncertain. Thus, the aim of the current study was to investigate the effect of MEG3 on EC via microRNA-149-3p (miR-149-3p).Methods: Gain- and loss-of-function experiments were initially performed in EC cells in addition to the establishment of a 4-nitroquinoline 1-oxide-induced EC mouse model aimed at evaluating the respective roles of forkhead box P3 (FOXP3), MEG3, miR-149-3p, mouse double minute 2 homolog (MDM2) and p53 in T cell differentiation and immune escape observed in EC.Results: EC tissues were found to exhibit upregulated FOXP3 and MDM2 while MEG3, p53 and miR-149-3p were all downregulated. FOXP3 was confirmed to be a target gene of miR-149-3p with our data suggesting it reduced p53 ubiquitination and degradation by means of inhibiting MDM2. P53 was enriched in the promoter of miR-149-3p to upregulate miR-149-3p. The overexpression of MEG3, p53 or miR-149-3p or silencing FOXP3 was associated with a decline in CD25+FOXP3+CD4+ T cells, IL-10+CD4+ T cells and IL-4+CD4+ T cells in spleen tissues, IL-4, and IL-10 levels as well as C-myc, N-myc and Ki-67 expression in EC mice.Conclusion: Collectively, MEG3 decreased FOXP3 expression and resulted in repressed regulatory T cell differentiation and immune escape in EC mice by upregulating miR-149-3p via MDM2-mediated p53. [ABSTRACT FROM AUTHOR]

The article presents a study of the effect of carbocisteine on acute exacerbation of chronic obstructive pulmonary disease (COPD). A discussion is presented of some of the components of COPD including airway inflammation, oxidative stress, and mucus hypersecretion. The use of carbocisteine, a mucolytic, is examined due to its antioxidative, anti-inflammatory, and mucolytic effects. The randomised, placebo-controlled, and double-blind methods used in the study are described. Also discussed is the recommendation by the authors concerning the use of carbocisteine for certain cases of COPD.

Ischemia-reperfusion (I/R) injury causes present challenges in the field of graft transplantation which is also a major contributor to early graft dysfunction or failure after organ transplantation. The study focuses on the effects of prolonged cold-ischemia (CI) on the autophagic activity in the graft lung in a rat orthotopic lung transplantation model. Donor lungs were preserved under CI conditions for different periods. An orthotopic lung transplantation model was developed, and the lung tissues from donor lungs subjected to CI preservation and reperfusion were harvested. We evaluated the effects of different CI periods on autophagy, reactive oxygen species (ROS) and glucose consumption. Additionally, the mechanism by which prolonged CI affected autophagy was investigated through determination of the molecules related to the mTOR pathway after treatment with 3-Methyladenine (3-MA), rapamycin and an adenosine triphosphate (ATP) synthase inhibitor oligomycin (OM). Prolonged CI led to increased activities of key glycolytic enzymes, glucose consumption and lactic acid production. Autophagy, ROS and glucose consumption were induced in the graft lung after I/R, which reached peak levels after 6 h and was gradually decreased. Most importantly, the perfusion treatment of 3-MA or OM decreased ROS level and autophagy, but increased the extent of mTOR phosphorylation, while the perfusion treatment of rapamycin induced ROS and autophagy. Taken together, autophagy mediated by a prolonged CI preservation affects the glucose consumption and ROS production in the graft lung via the mTOR signaling pathway. [ABSTRACT FROM AUTHOR]