bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of interlayer bonded bilayer graphene on friction
Authors: Li 李 Yao-Long 耀隆 , Tian 田 Zhen-Guo 振国 , Yin 尹 Hai-Feng 海峰 , Zhang 张 Ren-Liang 任良 
Published: June 2024

Abstract
We study the friction properties of interlayer bonded bilayer graphene by simulating the movement of a slider on the surface of bilayer graphene using molecular dynamics. The results show that the presence of the interlayer covalent bonds due to the local sp3 hybridization of carbon atoms in the bilayer graphene seriously reduces the frictional coefficient of the bilayer graphene surface to 30%, depending on the coverage of interlayer sp3 bonds and normal loads. For a certain coverage of interlayer sp3 bonds, when the normal load of the slider reaches a certain value, the surface of this interlayer bonded bilayer graphene will lose the friction reduction effect on the slider. Our findings provide guidance for the regulation and manipulation of the frictional properties of bilayer graphene surfaces through interlayer covalent bonds, which may be useful for applications of friction related graphene based nanodevices.
Stellarators with enhanced tritium confinement and edge radiation control
Authors: Boozer Allen H. 
Published: June 2024

Abstract
A stellarator design is described with the purpose of achieving three goals: (1) enhance the confinement time of tritium. (2) Have a sufficient density of high-Z impurities to radiate the thermal power escaping from the core while having an extremely low impurity density in the core. (3) Maintain a large fraction of the plasma in a burning plasma state with an optimal tritium fraction. Some features of this design could be used in tokamaks. Although having three confinement zones is natural for stellarators, it is not for tokamaks.
ICRH-related impurity source and control across experiments in H, D, T plasmas at JET-ILW
Authors: Chomiczewska A. , Gromelski W. , Ivanova-Stanik I. , Kowalska-Strzęciwilk E. , Wendler N. , Jacquet P. , Meigs A. , Mailloux J. , Menmuir S. , Karhunen J. , Lerche E. , Monakhov I. , Otin R. , Thomas B. , Dumortier P. , Van Eester D. , Barruzo M. , Bobkov V. , Brezinsek S. , Colas L. , Douai D. , Milanesio D. , Pawelec E. , Delabie E. , Lomanowski B. ,   JET Contributors
Published: June 2024

Abstract
The experimental and theoretical analysis were focused on experiments conducted to assess the effect of plasma isotopes, protium (H), deuterium (D), and tritium (T) on ion cyclotron resonance heating (ICRH) related plasma wall interactions. Comparison of L-mode discharges with N = 1 3He and N = 1 H minority ICRH heating scenarios were done for different isotopes. For the selected pulses, the behaviour of high-Z, mid-Z and low-Z intrinsic impurity and radiated power behaviour was investigated based on data from VUV, visible spectroscopy, and bolometry diagnostic at Joint European Torus. It was found that for N = 1 3He scenario during radiofrequency antennas operation, core W, Ni content, Be source and the radiated power are higher for π/2 in comparison to dipole antenna phasing. Lowest core Ni, W content and radiated power is clearly observed for H plasmas in comparison to D and T, where for this ICRH scenario behaviour was similar. However, lower Be photon flux is observed for T in comparison to D plasmas. Be sputtering by He particles is responsible for such an effect. Additionally, several computer simulations were conducted using the COREDIV code. The difference in the electron temperature was due to the difference in the isotope masses. Increased temperature in the central plasma in the case of T plasmas leads to higher radiation in the central plasma in comparison to H plasmas. As a result, the power across separatrix is lower and the temperature on the divertor plate decreases with the increase of the isotope mass. At these temperatures on the divertor plate, W is not sputtered by the main plasma ions H, D and T and by He. For the N = 1 H ICRH scenario clear difference between D and T plasma was observed with higher metallic impurity content for T plasma in comparison to D. Impurity content in the plasmas is found to be sensitive to the power balance between the antenna straps. Its minimum is observed for the maximum of P
cen/P
tot.
Autonomous Robots Traverse Multi-Terrain Environments via Hierarchical Reinforcement Learning with Skill Discovery
Authors: Wang Yifan , Yao Meibao 
Published: June 2024

Abstract
Although deep reinforcement learning (DRL) has been widely used in robotic mapless navigation tasks, most of the current research focuses on structured environments such as indoor or maze scenes, and little is targeted on outdoor environments. Unlike indoor environments and mazes, outdoor fields tend to be unstructured with complex landforms and sparse rewards for robotic navigation. The performance of most DRL-based strategies is directly affected by the design of the reward function, which greatly deteriorates its generalizability to outdoor environments. To this end, here we propose a two-stage learning paradigm based on skill discovery and hierarchical reinforcement learning (HRL) to cope with this challenge. Specifically, we implement skill discovery through a pre-training stage to acquire diverse skills with terrain-adaptive exploration strategies; then we select multiple skills using HRL to cope with more complex scenarios. We carry out the robotic multi-terrain traverse task based on a high-fidelity robotic simulation platform, Webots, and implement extensive comparative experiments and ablation studies to demonstrate the effectiveness of our approach.
Situation Awareness of Mars helicopter based on YOLOv7
Authors: Qi Yifan , Xiao Xueming , Yao Meibao , Zhang Lei , Fu Yuegang 
Published: June 2024

Abstract
Situation awareness on Mars is indispensable for various downstream applications such as navigation and path planning, mapping and scientific discover. However, current Mars rover platform suffered from the absence of global information, leading to mission reduction and the failure of global planning. Compared to the rover, Mars helicopter is a new type of attempt for Mars exploration, which can provide a wide range view of scenes to well support the above missions. To this end, in this paper we proposed a novel learning-based situation awareness model for Mars helicopter. We modified the Yolov7 model by embedding a new channel attention on its head to improve the accuracy of detection. Besides, we designed a Tiny-Scale Detection Module (TSDM) to capture small or hidden rocks in complex Martian surface. To achieve further refinement and validate our proposal, we built an open-source synthetic dataset in air view. After extensive experiments, our model achieved excellent outperforms than the baseline model in our Mars dataset.
Manipulator Control System Based on Gesture Recognition for Space Operation
Authors: Yang Kaiyu , Xiao Xueming , Lin Boyu , Zhang Lei , Fu Yuegang 
Published: June 2024

Abstract
In the scenario of on-orbit servicing, the complex space environment and the strict limitation of spacesuits made the manual control of manipulator extremely inconvenient. Current remote-control methods such as voice control, are commonly affected by the signal ratio, especially in the case of solar wind. Therefore, in this paper, we proposed a gesture-based remote-control system for real-time manipulation of the space manipulator in order to accomplish the onboard tasks. Gesture-based control strategy is more friendly on human-machine interaction than voice control or manual control. The proposed method: utilized gesture recognition technique to perform scheduled tasks according to the preset gestures. For preset missions, specific gestures are recognized and matched through KNN algorithm, and then manipulator is driven to execute the scheduled tasks. To validate the efficiency of the proposed method, extensive experiments are carried out on simulation platforms and compared with the traditional method of gesture recognition using rotation angle and gesture recognition using CNN. Results demonstrated that our method outperforms the other two solutions in terms of accuracy and speed.
Kinematic accuracy reliability evaluation method of space deployable mechanism based on dynamic model
Authors: Liu Chang , Zhuang Xinchen , Sun Zhongchao , Yu Tianxiang 
Published: June 2024

Abstract
Space deployable mechanisms are widely used in aerospace missions. The uncertainties in the geometric or physical parameters seriously affect the kinematic accuracy of the mechanism during the deployment process. In this paper, a kinematic accuracy reliability evaluation method of the space deployable mechanism based on dynamic model and adaptive hybrid surrogate models is presented. Firstly, the dynamic model of the space deployable mechanism is established based on the Lagrange method, and the motion error function considering the factors such as the mass, dimension and load is established. In order to improve the efficiency, an adaptive hybrid surrogate model reliability evaluation method based on improved weight measurement method is further proposed. The weight measurement method considers the global errors and local errors of the models. Finally, the Monte Carlo method is used to verify the accuracy of the hybrid surrogate model method. The relative error of the failure probability calculated by the proposed method is within 2.5 %, indicating that the proposed method has high calculation accuracy and efficiency.
Sparse linear parameter-varying autoregressive moving average modelling of non-stationary gearbox vibration signals
Authors: Li Zihan , Liu Xuemei , Chen Yuejian 
Published: June 2024

Abstract
Gearboxes frequently operate under variable speed conditions, leading to the non-stationarity of collected monitoring signals. This paper proposes a sparse linear parameter-varying autoregressive moving average (Spa LPV-ARMA) model for fault detection of gearboxes under variable speed conditions. The Spa LPV-ARMA model integrates the advantages of LPV concepts, sparse models, and ARMA models. The proposed model has a more compact structure compared to the reported Spa LPV-AR model, which results in a lower ratio of parameter number to data amount, and the compact model structure also allows the Spa LPV-ARMA model to have higher computational efficiency during the testing phase. A simulation study was conducted to validate the performance of the proposed method. The results demonstrate that the Spa LPV-ARMA model exhibits superior modeling accuracy compared to the reported Spa LPV-AR model. Additionally, the fault detection method based on the Spa LPV-ARMA model achieves a higher fault detection rate when contrasted with a model that solely considers the autoregressive component.
Analysis and Experimental Study on Vibration Isolation Performance of Full-scale Turbofan Engine Mounting
Authors: Wang Jian-Qiang , Nie Yan-Ping , Chen Yong-Hui , Qun Yan , Chen Chun-Lan , Dong Wan-Yuan 
Published: June 2024

Abstract
At present, most of the turbofan engine use the articulated link mount to connect the engine to the wing, and the analysis and experimental research of articulated link mount are important means in the development of engine mount. In this paper, the vibration isolation performance analysis of a certain turbofan engine mounting was carried out, and a full-scale turbofan engine mounting vibration isolation test platform was established based on the four-terminal parameter method, and the engine simulation device - eccentric rotation excitation tester was developed, which simulates the real engine vibration through rotor imbalance, and the vibration isolation efficiency of a certain type of engine mount at the high and low pressure rotor frequency was obtained. The results show that the simulation and test results are very close, the error is within 15% at the low-frequency, and the error is within 5% at the high-frequency. The research of this paper can provide test evaluation means for my country to independently carry out the design and improvement for large passenger aircraft engine installation devices, and provide test basis for its design and finalization.
Modal analysis of honeycomb panel satellite structure based on MSC Apex
Authors: Sun Risi , Liu Xuefeng , He Ningbo 
Published: June 2024

Abstract
Modal analysis plays an important role in the process of Satellite structure development. In this paper, the honeycomb sandwich plate and the satellite structure are taken as the research objects, and the corresponding finite element models are established. The analysis results of the actual modeling of honeycomb plate and the equivalent modeling of sandwich sandwich plate are obtained, and the fundamental frequency deviation of the whole satellite structure is discussed when the equivalent correction coefficient γ of honeycomb plate is different. The results show that the maximum relative error of the modal frequency between the equivalent method of sandwich sandwich plate and the actual modeling is 2.8%. Therefore, the equivalent method can be applied to large-scale finite element analysis and calculation, and the calculation efficiency can be improved. When the value of γ is 0.4∼0.6, the vibration modes of the whole satellite structure are basically consistent, and the maximum fundamental frequency difference is 10%. The results can evaluate the accuracy of the sandwich sandwich plate equivalent method for satellite mechanical analysis.
Dynamic Load Identification at Natural Frequencies for Aircraft via Attention Based 1D-CNN
Authors: He Wenbo , Li Baoqing , Feng Zhenyu , Zhang Xiaoqiang , Sun Hanyu 
Published: June 2024

Abstract
Since the frequency response function is ill-conditioned at the natural frequency of the system, the traditional load identification method based on the system parameters is no longer applicable. Aiming at the difficulty of dynamic load identification at the natural frequency of the structural system, a dynamic load identification method at the natural frequency of the structure based on one-dimensional convolutional neural network(1D-CNN) with attention mechanism is proposed. Specifically, the high-level features in the vibration response signal are first extracted through the convolution layer. Then the weight matrix of the network is updated by backpropagation algorithm, which represents the importance of different features. The mapping relationship between response and load is established to realize the task of load identification. From the trained data, the attention module learns the contribution of features according to the different contribution of different features to load prediction. The important components in the response signal are highlighted and noise pollution is suppressed. Excitation and response signals at the natural frequency of the system were acquired using exciters and an accelerometer mounted on the GARTEUR aircraft model. Excitation and response signals at the natural frequencies of the system are obtained by an exciter and accelerometer mounted on the GARTEUR aircraft model. The responses of the model at the first three natural frequencies of 6.4Hz,35.8Hz and 48.5Hz were obtained respectively. Experimental results show that compared with the traditional TSVD load identification method, the maximum error of this method is only 3.19%. Compared with the 1D-CNN method, the proposed method has stronger robustness under 20%, 50% and 80% noise levels.
Determining the start to degradation time of bearings using the improved diversity entropy
Authors: Zhang Jingyi , Bai Rui 
Published: June 2024

Abstract
Rolling element bearing is an essential part of rotating components. If the rolling element bearing is broken, it may cause damage to the system and even pose a threat to life health, and property safety. Therefore, the rolling element bearing’s health condition needs to be monitored and forecasted, thereby reducing unplanned downtime and improving bearing productivity. It is also important to determine the start to degradation time (SDT) when monitoring and predicting the condition of rolling bearings. Determining the SDT can help monitor the degradation process of the bearing so that it can be repaired or replaced in time. To facilitate the determination of the SDT of the bearing, a new method is proposed to adaptively determine the SDT of rolling element bearings by using the improved diversity entropy. In this way, early warning signs can be provided on time by determining the SDT. The run to failure experimental results show that the proposed improved diversity entropy method based determination of rolling bearing’s SDT has broad application prospects.
A novel feature mode decomposition method and its application for gear fault detection
Authors: Shi Huifang , Miao Yonghao , Lin Jing 
Published: June 2024

Abstract
Fault detection can promptly reveal the potential hazards of mechanical equipment, guaranteeing the safety, stability, and reliability of their operation. Although many advanced fault detection methods, such as spectral kurtosis, deconvolution and decomposition, have been developed, most of them still suffer from insufficient utilization of fault features and incomplete extraction of diagnostic information. Given this, we propose a novel method named feature mode decomposition (FMD). Firstly, to coarsely steer the decomposition direction, a finite impulse response (FIR) filter bank is set up with a window initialization. The, correlated kurtosis (CK) is taken to evaluate the latent fault-related information in mode signals, thereby guides the updating process of all adaptive filters, assisted with period estimation. Ultimately, the unnecessary and intermingled modes are weeded out by mode selection. Experimental cases verified that the proposed FMD can adaptively decompose the fault mode of gear fault signal with excellent inspection ability. Comparison between the results and those of the classical variational mode decomposition (VMD) further highlights that FMD is more robust to other interference and noise.
Research on non-contact dynamic stress calibration method of fan blade on simulation
Authors: Zhang Qiangbo , Dong Jiang , Zhang Shuai 
Published: June 2024

Abstract
In order to establish the non-contact measurement method of fan blade dynamic stress, the most important thing is to establish the method of fan blade dynamic stress calibration. In this paper, the static virtual loading and harmonious response analysis of fan blades in the simulation platform, and the calibration equation between the blade tip displacement and the blade dynamic stress is established. Finally, the calibration equation is verified and the error analysis is carried out by simultaneously carrying out contact and non-contact dynamic stress measurement tests on the rotor test bench.
Research on structural damage identification method of aircraft aluminium alloy skin based on power spectral entropy
Authors: Zhou Qiting , Sun Dingyi , Shen Ao , Xu Jianhao , Li Yongbo 
Published: June 2024

Abstract
Skin is an important structural component which covers the surface of aircraft widely, the structural health of skin has a great impact on the overall safety of aircraft. Due to the harsh operating environment, complex and changing working conditions, and high-intensity service process of aircraft, it is easy to cause damage to the skin. Thus, the in-situ health monitoring for aircraft skin is an effective approach to ensure its safety and reliability. Thanks to the ability of Lamb waves to propagate over long distances and recognize small-scale defects, they have shown great potential in the health monitoring of thin-walled structures and have received widespread attention. However, the traditional Lamb wave-based damage identification methods generally suffer from the problems of large number of sensors and low efficiency. Therefore, a skin damage identification method based on power spectral entropy is proposed in this paper, which can estimate the damage extent by extracting the nonlinear component increase caused by damage, and the experiments validate that the proposed method has higher sensitivity and computational efficiency than the existing other entropy-based methods.
Effects of viscosity and launch pressure on variations of the maximum impact acceleration in cross media water-entry process
Authors: Han Xiangdong , Li Chao , Wang Xiquan , Li Junzhi , Yun Kang , Li Zhe , Liu Baowei 
Published: June 2024

Abstract
The aim of the investigation was to experimentally discuss effects of viscosity and launch pressure on variations of the maximum impact acceleration in cross media water-entry process. For different launch pressures, they reflected effects of motion peculiarity. They were 2.5MPa, 2.75MPa, and 3.0MPa. Variations of viscosity explained influences of property of operating environment. Via the change of lithium bromide solution mass fraction, various viscosities were got. The mass fractions employed were 1%, 2%, and 3%. Results indicated that the maximum impact acceleration grew steadily with the increment of lithium bromide solution viscosity. When launch pressure grew, the maximum impact acceleration increased gradually. Comprehensively, effect degree of viscosity was more intense than that of the launch pressure.
Experimental investigation on effects of temperature and launch pressure on variations of the impact acceleration in cross media water-entry process
Authors: Han Xiangdong , Wang Xiquan , Li Chao , Chen Junbiao , He Lei , Yu Fangyan , Hu Xin 
Published: June 2024

Abstract
In the paper, effects of temperature and launch pressure on variations of the maximum impact acceleration in cross media water-entry process are systematically investigated via experiments. Results indicated that under the water entry angle of 25°, the maximum impact acceleration increased gradually with the growing of launch pressure from 2.5MPa to 3.0MPa when the temperature is 30°C, 40°C, and 50°C. The maximum impact acceleration decreased constantly with the increase of the temperature from 30°C to 50°C when launch pressure is the constant. According to the comprehensive analysis, effect degrees of variations of the launch pressure on the maximum impact acceleration are more significant than that of the variations of temperature.
Research on dynamic sealing performance of sealer structure under the influence of temperature
Authors: Lu Rende , Cheng Wenjia , Wei Ruitao , Li Liangqing , Lu Daosheng , Ren Xiaoyang 
Published: June 2024

Abstract
Affected by the extreme environment of high temperature and high pressure downhole, the mechanical behavior of the sealer rubber sleeve undergoes significant changes during service, leading to a sharp decline in the mechanical properties of the rubber material within the high-temperature environment. To address the issue of seal failure in the sealer rubber barrel under high-temperature loads, experimental investigations were conducted to analyze the compression properties of rubber materials at various temperatures. The constitutive parameters of the rubber were then fitted using the Reduce-Polynomial model. Subsequently, a finite element model was employed to study the sealing performance and mechanical response of the three-compartment rubber-tube structure sealer at different temperatures. The findings demonstrate that temperature fluctuations have a substantial impact on the sealing performance and bearing strength of the sealer. Consequently, this research holds crucial guiding significance for the structural design of the sealer rubber cylinder under high-temperature conditions.