To investigate the role of RNA m6A methylation in mediating cerebellar dysplasia through analyzing the phenotypes of the mouse cerebella and the expression of several key m6A regulators upon ...hypobaric hypoxia treatment.
Five-day old C57/BL6 mice were exposed to hypobaric hypoxia for 9 days. The status of mouse cerebellar development was analyzed by comparing the body weights, brain weights and histological features. Immunostaining of cell-type-specific markers was performed to analyze the cerebellar morphology. Real-time PCR, Western blot and immunohistochemical staining were performed to detect the expression of key m6A regulators in the mouse cerebella.
Compared with the control, the body weights, brain weights and cerebellar volumes of hypobaric hypoxic mice were significantly reduced (
0.01). The expression of specific markers in different cells, including NeuN (mature neuron), Calbindin-D28K (Purkinje cell) and GFAP (astrocyte), was decreased in hypobaric hypoxic mouse cerebella (
0.01), accompanied with
•A model with non-equilibriumtransformationis developed for laser welding of Ti6Al4V.•The welding temperature field is improved by considering non-equilibrium.•The simulation under non-equilibrium is ...sufficient and reliable after modifying once.
The effect of non-equilibrium solid state phase transformation on numerical simulation of welding temperature field is researched during keyhole mode laser welding of Ti6Al4V alloy. The simulation of the welding temperature field considering equilibrium phase transformation is obtained by means of the model of the heat transfer and fluid flow after the keyhole presetting. Based on the simulation considering equilibrium phase transformation, the simulation considering non-equilibrium phase transformation is modified, in terms of partitioning the regions and endowing the physical parameters considering non-equilibrium phase transformation. Compared with those considering equilibrium phase transformation in the horizontal planes, the temperature contours greater than or equal to 1300 K considering non-equilibrium phase transformation are elongated, while the temperature contours between 1100 K and 1300 K considering non-equilibrium phase transformation are shortened. The difference of the welding temperature fields considering equilibrium and non-equilibrium phase transformations basically emerges in the cooling stage. The temperature fields considering non-equilibrium phase transformation after modifying once and twice are almost the same, signifying that the simulation considering non-equilibrium phase transformation after modifying once is sufficient. The computational results considering non-equilibrium phase transformation agree well with the experimental ones in contrast with those considering equilibrium phase transformation, showing that the simulation considering non-equilibrium phase transformation after modifying once is reliable and satisfactory.
By incorporating the merits of fractional-slot concentrated windings and Vernier machine structure, a new multi-pole dual-structure permanent magnet (PM) machine is proposed for low speed, ...direct-drive applications in this paper. In the outer stator, a fractional-slot concentrated winding is adopted to reduce the slot number and stator yoke height, hence saving space and improving torque density. In the inner stator, a Vernier structure is used to reduce the winding slots, thereby enlarging the slot area to accommodate more conductors, thus the inner stator space is fully utilized. Consequently, the merits of these two structures can be ingeniously integrated into one compact PM machine and the torque density is improved, cogging torque is reduced and the control flexibility with two sets of independent stator windings is increased. By using time-stepping finite element method with curvilinear elements for moving between the stator and the rotor, the steady state and transient performances of the PM machine are simulated and the validity of proposed dual-structure PM machine is verified.
Finite-element method (FEM) has been widely used to analyze the performance of electric devices. Due to the nonlinear permeability of iron materials, Newton-Raphson method is usually used in FEM for ...nonlinear iteration. To accelerate the nonlinear convergence, one effective technique is proposed. The method is to use different relaxation factors for materials in the electric device. The difference between this proposed method and conventional method is that in conventional method only one relaxation factor is used for all solutions. With the proposed method the total computing time of iteration process of FEM can be reduced effectively. The proposed algorithm is tested on a highly saturated transformer to showcase its effectiveness.
The significance of eddy-current in high-speed permanent magnet machines cannot be underestimated in that it has serious implications on the machine's efficiency or even demagnetizes the PMs because ...of an overheating problem. It is necessary to accurately estimate the eddy-current losses and find an optimal design to minimize the losses and improve the machine's performance. In this paper, the axial segmentation of the PMs is first employed to cut off the eddy-current axial paths. Then, a conductive shield is introduced to smooth the time varying magnetic field in the conductive sleeve and the PMs in order to reduce the eddy-current losses. A nodal method based network-field coupled multislice time-stepping finite element method (TS-FEM) is proposed to analyze the steady-state and dynamic characteristics of the high-speed PM machine; its merit is that sub-block matrixes of the circuit equations are more convenient to be established compared with that of mesh method. Analysis of eddy-current losses in the rotor is reported.
In this paper, an efficient and effective magnetic circuit model is developed for the analysis of a magnetless double-rotor flux switching motor. First, a magnetic circuit network for the proposed ...machine is built, and formulas for the calculation of the magnetic components in the circuit, including the permeances of teeth, yokes, slots, leakage permeances, and air-gap permeances, are derived. Then, by applying Kirchhoff's current law to each node in the network, nodal analysis is used to solve the matrix equation. All the circuit variables, and hence the complete motor magnetic characteristics are being considered. When the rotor rotates, the air-gap permeances are adjusted accordingly, and the above calculations are repeated, so as to find the complete static performance of the motor. Last, the validity and the effectiveness of the proposed method are verified using both the experimental results and the simulation results obtained from the time-stepping finite-element method.
A novel dual-stator bidirectional-flux modulated permanent magnet (PM) machine is presented in this paper. The key of the design is to locate consequent PM poles in both stator and rotor sides and ...the merit is that the magnetic flux produced by either the rotating or stationary PMs and dual-stator windings can be modulated by the stator teeth and rotor iron segments. It is shown that with this flux modulation effect and improved reluctance torque effect, the torque density of the machine can be increased. The bidirectional flux modulation theory and operation principle of the machine are explained and analyzed using time-stepping finite element method.
A novel brushless electric continuous variable transmission (E-CVT) system is presented and optimized. The proposed system offers an alternative solution for a variable-speed constant-frequency ...operation of the wind turbine application. The key is to eliminate the gearbox and brushes in the machine and this E-CVT system comprises of two rotors and two stators within one machine. This design inherits and integrates the merits of the direct-drive permanent magnet generator and the doubly fed induction generator with the additional benefit of the improved torque density and the need for a low-cost partial-scale converter. The structure, operation principle, and performance are analyzed. Genetic algorithm is employed to optimize the parameters for maximizing its power density. Time-stepping finite-element method is used to analyze the dynamic performance of the proposed system.
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