The charging performance of lithium-ion batteries is significantly affected by the polarization effect, which leads to increased resistance and prolonged charging time. this paper combines experimental testing with nu...
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Underwater Vehicles are very important underwater operation equipment, and a new underwater vehicle is designed in order to realize the measurement of the ship draft. The design is based on the ROV(Remote Operated Veh...
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Underwater Vehicles are very important underwater operation equipment, and a new underwater vehicle is designed in order to realize the measurement of the ship draft. The design is based on the ROV(Remote Operated Vehicle) structure, and the mobile power supply and the upper computer are mounted on the underwater vehicle body, aiming to accomplish the task of disconnecting the underwater vehicle from the cable under complex sea conditions. In this paper, the system communication and power supply scheme design, thruster arrangement, the center of gravity and floating center position design, and 3D model design are completed in turn to obtain a structural design scheme of the underwater vehicle based on the actual engineering background. Subsequently, the strength check of the overall frame was carried out based on ANSYS WORKBENCH, which proved that the material selection and structural design met the reliability requirements. Finally, the hydrodynamic characteristics of the robot were analyzed using ANSYS CFD.
In this paper,a numerical investigation into a spike-type rotating stall process is carried out considering a transonic compressor rotor(the NASA Rotor 37).Through solution of the Unsteady Reynolds-Averaged Navier-Sto...
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In this paper,a numerical investigation into a spike-type rotating stall process is carried out considering a transonic compressor rotor(the NASA Rotor 37).Through solution of the Unsteady Reynolds-Averaged Navier-Stokes(URANS)equations,the evolution process from an initially circumferentially-symmetric near-stall flow field to a stable stall condition is simulated without adding any artificial *** the near-stall operating point,periodic fluctuations are present in the overall flow of the ***,the blockage region in the channel periodically shifts from middle span to the *** fluctuating condition does not directly lead to stall,while the full-annulus calculation eventually evolves to ***,a kind of“early disturbance”feature appears in the dynamic signals,which propagates forward ahead of the rotor.
In order to realize a multi-channel exhalation detection device with large dynamic range and high precision, a well designed signal processing and sampling circuit is essential for gas sensors. In this paper, a partic...
In order to realize a multi-channel exhalation detection device with large dynamic range and high precision, a well designed signal processing and sampling circuit is essential for gas sensors. In this paper, a particular circuit is designed to meet above requirement. The proposed circuit uses a constant current source to achieve linear transformation of resistance value and output voltage, and uses a voltage follower for impedance transformation to minimize the impact of the AD acquisition on the front-end circuit. Since the gas sensor can be regarded as a variable resistor, the proposed circuit is tested with variable resistors varying from 10k$\Omega$ to 50M$\Omega$, over three orders of magnitude. In order to increase the sensitivity of the gas sensors, it is need to heat the sensor. Then a multi-channel heating circuit is designed with independent adjustable heating current in each channel, which can be controlled with multi-channel PWM signal from the MCU. With simulation and experiment, the performance of the proposed circuit has been verified to be excellent. Furthermore, the circuit has the advantage of being used in various fields.
To address the challenges associated with the real-time characterization of in situ rock strength parameters during drilling operations, a coupled bit–rock interaction model was developed using Ls-Dyna. Through expli...
To address the challenges associated with the real-time characterization of in situ rock strength parameters during drilling operations, a coupled bit–rock interaction model was developed using Ls-Dyna. Through explicit dynamic simulations of rock fragmentation processes, this paper investigates the evolution of drilling-induced dynamic response characteristics (e.g., torque, response force, vibration amplitude, and energy consumption) and their inherent correlations with uniaxial compressive strength (UCS) values. Simulation results demonstrate significant positive correlations between torque, response force, vibration, and energy characteristics with rock UCS, while drilling speed exhibits a strong negative correlation. To validate these findings, a micro-drilling test platform was developed, and a response while drilling test method based on constant drilling speed–rotation speed was proposed. Experimental results indicate that longitudinal vibration peak-to-peak amplitudes for yellow rust stone (95 MPa), artificial rock (58.2 MPa), curb (57.5 MPa), and sandstone (45 MPa) reached 1.677 g, 0.981 g, 0.745 g, and 0.535 g, respectively, while average power consumption values were 4196.9W, 3839.5W, 3610.9W, and 3572.7W, respectively, which verifies the correctness of the relationship between dynamic response characteristics and rock UCS value. The research results provide a theoretical basis for adjusting the operation parameters of the rig reasonably and realizing the adaptive drilling of the rig under different formations.
Introducing purely nonlinear elastic elements can induce rich dynamic behaviors, such as bifurcations, jumps and isolated resonance curves, to linear systems. Therefore, these elements are suitable for constructing st...
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Due to the merits of high flow rate and high lift, double-suction centrifugal pumps are widely used for agricultural irrigation along the Yellow River in northern China. The operational conditions of the pump are high...
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Soft pneumatic actuators (SPAs) have demonstrated the ability to generate contraction, expansion, and bending strokes in three-dimensional space during pressurization. Gripper composed of SPAs are expected to serve as...
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Road damage detection is particularly essential for improving road traffic safety. Existing methods do not perform well due to complex road conditions and sparse features contained in road damage. Therefore, we propos...
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ISBN:
(纸本)9781665480468
Road damage detection is particularly essential for improving road traffic safety. Existing methods do not perform well due to complex road conditions and sparse features contained in road damage. Therefore, we propose a new road damage detection network - YPLNet, which could obtain more refined multi-scale contextual features. Specifically, the network proposed in this paper is based on YOLOv5, by adding the PSA module to the backbone network, the spatial information of the feature map at multi-scale is obtained to enrich the feature space, and the long-term information dependence between channels is further constructed. In addition, in the feature fusion stage, the LCFI module is utilized to obtain contextual features under the multi-scale receptive fields, and these contextual features include rich low-level and high-level information. Our proposed network achieves a Mean-F1 Score of 0.635 in the competition. The source code and model are publicly available at https://***/hehualin-tut/YPLNet
Taking advantage of the gradual change characteristic of the curvature of the conventional conic ellipse, this paper proposes a method of fitting a non-uniform rational basis spline (NURBS) curve with an elliptical ar...
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