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To develop a simplified and highly accurate ship motion model, this study thoroughly investigated the relationship between the dimensionless cross-flow coefficient and the four hydrodynamic derivatives of the Norrbin model. Eight different types of ships were simulated to explore the impact of dimensionless cross-flow coefficients and individual hydrodynamic derivatives on the ship's turning circle. A set of precise formulas is proposed to depict the interplay between these variables. The simulation outcomes indicate that the average deviation in the agreement between the turning circles produced by adjusting the dimensionless cross-flow coefficient and those predicted by modifying the four hydrodynamic derivatives was only 2.70%. Furthermore, the similarities between the two circles and the sea trail were significantly higher at 91.45% and 92.87% compared with the original Norrbin model's accuracy of 78.12%. Adjusting the dimensionless cross-flow coefficients enabled the rapid identification of a curve that closely mirrored the sea trail. This research aimed to improve the accuracy of the Norrbin model and resolve issues related to determining the magnification of the hydrodynamic derivatives, laying a robust foundation for subsequent studies and applications in relevant domains. [ABSTRACT FROM AUTHOR]

Based on the complex structural characteristics of permanent magnet-assisted synchronous reluctance motors (PMA-SynRMs), this paper proposes a multi-objective optimization design method for the motor using a composite algorithm. Firstly, the power density, electromagnetic torque, cogging torque, and torque fluctuation coefficient were used as optimization targets based on parametric analysis data of 14 motor structure variables, where parametric sensitivity analysis helped select eight optimization variables. Secondly, the motor prediction model was fitted using the genetic algorithm–back propagation (GA-BP) neural network. Finally, non-dominated sorting genetic algorithm-III (NSGA-III), based on the reference points, was used to find the optimization of the prediction model and complete the multi-objective optimization design of the external rotor PMA-SynRM with eight inputs and four outputs. A comparative analysis of the electromagnetic performance of the motor before and after optimization verifies the feasibility of optimizing the motor using the composite algorithm. This paper provides an analytical tool for the multi-parameter and multi-objective PMA-SynRM optimization design. [ABSTRACT FROM AUTHOR]

In response to the structural optimization problem of PCB stator coreless disc motors, the orthogonal response surface method was used to optimize the motor structure, preliminarily determine the basic parameters of the motor, and conduct orthogonal experiments on the motor parameters based on the optimization design objectives. The optimization factors were the quantity of the magnetic pole of the motor rotor p, the ratio of the main/auxiliary pole sizes Rnd, the thickness Tm of the permanent magnet, and the air gap length δ. The motor torque Td, the amplitude of the magnetic density of the air gap Bδ, and the waveform distortion rate THD were used as optimization objectives. The motor parameters that cause the motor torque to reach a maximum cause the air gap magnetic density to reach a maximum and the waveform distortion rate to reach a minimum. Due to the use of PCB plates instead of motor stator cores in the PCB coreless disc motors, the service life of the PCB board during motor operation will be reduced with the temperature increase generated by the stator winding. To solve this problem, a response surface analysis of the motor was carried out to reduce the increase in the temperature of the stator windings during the operation of the motor. The PCB board and stator winding are the main factors affecting the motor's temperature increase. Taking the thickness of the PCB board, the hole diameter on the board, and the uneven width of the stator winding as optimization factors, the motor parameters with the lowest increase in the temperature of the motor winding were obtained. A simulation analysis was conducted using Ansys/Maxwell software, and the results prove the feasibility of the optimization. [ABSTRACT FROM AUTHOR]

To systematically and comprehensively analyze the effects of different aging environments on the aging failure of aluminum alloy/CFRP (Carbon Fiber Reinforced Plastics) composite bonded shear and butt joints, seven typical aging environments of room temperature (23°C/20%RH, RT), high-temperature (80°C/20%RH, HT), low temperature (−40°C, LT), temperature cycles (−40 ~ 80°C/20%RH, TC), immersed in water at room temperature (IRT), high temperature and high humidity (80°C /95%RH, HTHH), and hygrothermal cycles (−40°C ~ 80°C /95%RH, HC) were selected to perform aging tests. The composition analysis revealed that the adhesive underwent the most significant post-curing in HT, followed by TC, while LT had almost no effect on the adhesive. It was also found that the degree of moisture absorption and hydrolysis of the adhesive in IRT, HTHH and HC decreased sequentially. A single temperature or humidity environment had small effect on the failure strength of bonded joints less than 20%, increasing temperature or humidity could further reduce the failure strength by about 30%, and periodically changing the temperature or humidity had the greatest effect on the failure strength by more than 40%. ANOVA (Analysis of Variance) shows that all the single factors of aging time, load type, or aging environment had significant effects on the failure strength, but the aging environment had the greatest effect. Multifactor coupling effects on the failure strength was not significant, except for the coupling effects of aging environment and aging time. [ABSTRACT FROM AUTHOR]

Quasi-one-dimensional (Q1D) semiconductor antimony selenide (Sb2Se3) shows great potential in the photovoltaic field, but the photoelectric conversion efficiency (PCE) of Sb2Se3-based solar cells has shown no obvious breakthrough during the past several years, of which the intrinsic reasons are pending experimentally. Here, we prepare high-quality Q1D Sb2Se3 thin films via the vapor transport deposition technique. By investigating the bandedge electronic level structure and carrier relaxation/recombination dynamics, we find that (i) the optimized Se-rich growth conditions can highly improve the crystal quality of the Q1D Sb2Se3 thin films, the carrier lifetime of which is substantially increased up to ∼8.3 μs; (ii) the Se-rich growth conditions have advantages to annihilate the deep selenium vacancies VSei (i = 1 and 3 for non-equivalent Se atomic sites) but is not effective for the deep donor VSe2, which locates at ∼0.3 eV (300 K) below the conduction band and intrinsically limits the PCE value of devices below ∼7.63%. This work suggests that further optimizing the Se-rich conditions to technically eliminate this kind of deep defect is still essential for preparing high-performance Sb2Se3 film solar cells. [ABSTRACT FROM AUTHOR]