Abstract: An analysis of a surface mounted permanent magnet (SPM) machine by a 2D meshless method is provided. The 2D meshless method includes steps: discrete nodes are arranged in the region to be solved; based on Taylor expansion and weighted least squares principle, the derivative value of vector potential can be approximated as a linear combination of vector potential values of each node in the support region; partial differential equations are converted into algebraic equations; by solving the algebraic equations, the vector potential of each node can be calculated, and then the distribution of the flux line and the flux density can be obtained. According to the electromagnetic calculation constraints of the machine, parameters such as the back electromotive force and electromagnetic torque of the machine can be obtained.

Abstract: The present disclosure provides an ecological governance method based on erosion prevention and control for a gentle slope farmland and relates to the technical field of ecological governance of farmlands. The ecological governance method based on erosion prevention and control for a gentle slope farmland includes the following steps: sampling a gentle slope farmland to investigate erosion thereof; and determining erosion of a gentle slope cultivated land and selecting a corresponding recovery strategy based on a detection result of a sample, a soil quality index (SQI), and a comprehensive vegetation quality index (VQI), where the recovery strategy includes a natural recovery method and a biological-farming comprehensive recovery method; enclosing the gentle slope cultivated land, fallowing the gentle slope cultivated land and reducing tillage; exterminating insect pests and poisonous weeds in the enclosed area; and turning over straws under soil by a cultivator. The growth of poisonous weeds is inhibited.

Abstract: The present disclosure provides a method for reducing the electromagnetic vibration of a fractional slot concentrated winding (FSCW) permanent magnet (PM) motor, which provides a guidance for the low vibration design of FSCW PM motor. The implementation of the method includes: Based on Nyquist Shannon sampling theorem, the modulation effect of electromagnetic force in the air gap is obtained, and the electromagnetic force component that contributes the most to the electromagnetic vibration of the FSCW PM motor is determined. The equivalent analytical model of PM flux density is established to obtain the phase relationship between different flux density harmonics. According to Maxwell stress equation, the internal relationship between each order of flux density harmonics and electromagnetic force harmonics is obtained. A new magnet structure of the PM motor is designed, and specific flux density harmonics are injected to reduce the electromagnetic force and electromagnetic vibration of the FSCW PM motor.

Abstract: An example self-priming microfluidic structure can include a microfluidic channel including a floor and a ceiling. A channel height is defined as a distance between the floor and the ceiling. A channel height step can be in the floor, or ceiling, or both. The channel height downstream of the channel height step can be greater than the channel height upstream of the channel height step. An interior pillar can be positioned in the microfluidic channel extending from the floor to the ceiling. The interior pillar can include a widening portion at an upstream end of the interior pillar and a tapering portion at a downstream end of the interior pillar. The interior pillar can overlap the channel height step so that the interior pillar is partially upstream of the channel height step and partially downstream of the channel height step.