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Deck motion prediction and compensation are critical technologies for carrier-based aircraft automatic landing. Traditional deck motion prediction methods rely on precision of motion models and parameter adjustments, facing challenges in adaptability to complex sea conditions, different types of carriers, changes in flight conditions, and limitations in prediction duration, as well as reliability issues. This paper proposes a deck motion prediction method based on the neural kernel network Gaussian process regression (NKN-GPR) model. The NKN-GPR model can utilize a neural kernel network (NKN) to automatically construct the Gaussian process regression (GPR) model′s composite kernel, effectively addressing the limitations of the automated kernel search (ACKS) algorithm, which heavily depends on manual prior knowledge. Simulation data is generated using a combination of sine wave and power spectrum models, and the NKN-GPR model is compared with an autoregressive (AR) model based on least squares in a simulated validation. The simulation results demonstrate that the NKN-GPR model exhibits significant advantages in motion prediction accuracy, smoothness, and prediction duration, which confirms the effectiveness of the proposed algorithm. This study provides theoretical support for safe automatic landing of carrier-based aircraft.

With the increasing demand for passenger transportation such as tourism railways, the application of small-capacity maglev vehicles is becoming more widespread. To investigate the dynamic performance of a small-capacity, medium-and low-speed maglev vehicle with a new levitation frame, suitable for a 1 400 mm track gauge, a rigid-flexible coupling dynamic model was established using SIMPACK software. Simulations calculated the straight-line vibration state and curve-passing capability, comparing the dynamic performance of the medium-and low-speed maglev vehicle with the existing levitation frame, focusing on vibration acceleration and curve-passing performance. The results showed that the levitation gap fluctuation of the new levitation frame under straight-line travel conditions was significantly different from that of the existing levitation frame structure, but both remained within the safe range. There was no significant difference in vibration acceleration of the vehicle body and the levitation frame between the two structures. When passing through the R50 m small-radius curve, compared with the existing levitation frame structure, the maglev vehicle with the new levitation frame had a smaller roll angle, with a maximum value of 0.97°, and a larger air spring lateral displacement, with a maximum value of 7 mm. When passing through the R550 m medium-radius curve, there was no significant difference in the body roll angle and lateral displacement between the two levitation frame structures. The maximum roll angle of the vehicle body was 0.65°, and the maximum lateral displacement was 23 mm. The lateral displacement of the air spring in the new frame structure was larger than that in the existing one, with a maximum value of 10 mm. The simulation analysis shows that the new levitation frame has good straight-line and curve-passing performance. [ABSTRACT FROM AUTHOR]

To investigate the feasibility of a radial bogie for 33 t axle-load diesel locomotives, a radial bogie scheme for large-axle load diesel locomotive was designed based on the concept, structure, and principle of the radial bogie. A dynamics model was constructed in multi-body dynamics software, and the adhesion coefficients, creepages and wear power of the leading wheelset were compared for heavy duty locomotive with the radial bogie and the conventional bogie while passing the curves. Through calculation and analysis, it is found that compared with the conventional bogie, the radial bogie may decrease the wheel slip momentum, improve the adhesion availability of locomotive when passing curves, reduce the wheel-rail wear and inconsistent wear of the left and right wheels, and decrease the frequency of wheelset repairs, which provides valuable insights for the development of large axle-load and high adhesion diesel locomotives. [ABSTRACT FROM AUTHOR]

Based on Gaussian 16 software, the structures of reactants and products in diazotization and coupling reactions of p-aminobenzene sulfonic acid are studied using the B3LYP and B2PLYP methods in density functional theory. By calculation and simulation, the geometry and electron distribution of the reactants and products are optimized. The results show that the enthalpy change of the diazotization reaction is -117 kJ/mol, and the Gibbs free energy change is -160 kJ/mol. The enthalpy change of the coupling reaction is -484 kJ/mol, and the Gibbs free energy change is -460 kJ/mol, indicating that both diazotization and coupling reactions are exothermic and irreversible. The thermodynamic calculations of diazotization and coupling reactions of p-aminobenzene sulfonic acid provide a theoretical basis for controlling reaction process conditions and thermodynamic research. [ABSTRACT FROM AUTHOR]

The 10m chord versine is commonly used as the standard to evaluate track irregularity in medium and low speed maglev (MLSM). However, the amplitude frequency of the mid-chord offset method suffers distortion, which is more serious in the short waveform range, and the 10m chord versine will lose a lot of short waveform signals. Therefore, 10m chord versine cannot be used in engineering practice as the true track irregularity. To solve this problem, the method of numerical simulation is used to simulate the process mid-chord offset method. By comparing the errors of 10m chord versine in time domain and frequency domain, the exactness of the "deduced from small to large" algorithm is verified, and two inverse algorithms of "deduced from small to large" are established to obtain the chord versine of small chord length, expand the effective detection range of short waveform irregularity, and the method of "inverse filtering" is used to inverse the short waveform irregularity. The results show that the two inverse algorithms of "deduced from small to large" can well deduce the chord versine of small chord length, and the minimum chord length that can be deduced is twice the step length. Therefore, in order to expand the measurement range of short waveform, the sampling step length should be reduced as much as possible. Compared with model B, model A has a larger error due to the addition of boundary conditions, some outliers appear, step signals appear in the power spectral density, and the absolute error is within 0.025 mm. Model B has high accuracy and good transfer characteristics, and the absolute error can be controlled within 0.001 5 mm. The field measurement of 10m chord versine of F-shaped track of Changsha Maglev Express Line shows that the track irregularities in the wavelength range of 0.5~100 m can be effectively inverted with both models. [ABSTRACT FROM AUTHOR]