bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of the main neutral species densities and temperatures in iodine plasmas using optical absorption techniques
Authors: Esteves Benjamin , Blondel Christophe , Chabert Pascal , Michel Tanguy , Drag Cyril
Published: December 2023

Iodine is a promising propellant for future plasma thrusters used in space propulsion. It is therefore important to understand the basic physics and chemistry of low-pressure iodine plasmas. In the present work, optical absorption methods are used to measure the densities of iodine molecules, I2, and iodine atoms, I, the translational temperature of the atoms and the dissociation fraction. The plasma is generated in a long quartz tube by a capacitively coupled RF discharge, and the pressure is varied between a few Pa and a few tens of Pa. The translational temperature of the atom vapour increases both with RF power and with pressure and reaches 1000 K at 50 W and 25 Pa. The molecules appear to be efficiently dissociated, with a dissociation fraction found above 65%, on average along the line-of-sight, at 120 W and 5 Pa. The population of the upper,

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, fine-structure level of the atomic ground term is found to be negligible, which confirms the existence of a high quenching rate, due to collisions with molecules and/or atoms. These measurements can be helpful for chemistry models of iodine plasmas.
Pulsed laser deposition of Sb2S3 films for phase-change tunable nanophotonics
Authors: Kepič Peter , Liška Petr , Idesová Beáta , Caha Ondřej , Ligmajer Filip , Šikola Tomáš
Published: December 2023

Non-volatile phase-change materials with large optical contrast are essential for future tunable nanophotonic applications. Antimony trisulfide (Sb2S3) has recently gained popularity in this field due to its low absorption in the visible spectral region. Although several Sb2S3 deposition techniques have been reported in the literature, none of them was optimized with respect to stoichiometry, lowest possible absorption, and large refractive index contrast (Δn) upon the phase change. Here we present a comprehensive multi-parameter optimization of pulsed laser deposition of Sb2S3 towards this end. We correlate the specific deposition with the resulting compositional and optical properties and report parameters leading to films with extraordinary qualities (Δn = 1.2 at 633 nm). Additionally, we suggest crystal orientations and vibrational modes associated with the largest change in the refractive index and propose them as useful large-scale indicators of the Sb2S3 switching contrast.
Triaxial rotor in the O(6) limit of the interacting boson model
Authors: Teng Wei , Wang Sheng-Nan , Zhang Yu , Fortunato Lorenzo
Published: December 2023

A mapping from the triaxial rotor Hamiltonian to that of the O(6) limit in the interacting boson model (IBM) is established, which is achieved by introducing the symmetry-conserving high-order interactional terms The validity of the proposed mapping scheme is further examined for the cases with γ = 0 and γ = π/6, respectively. It is shown that the rotor model results can be well reproduced in its O(6) image especially for the low-spin states. It thus provides an alternative way to understand the triaxiality in the finite-N systems and additional insight into the O(6) IBM theory.
Analysis of the self-consistency of nucleation in the diffuse interface limit of binary alloy phase field models
Authors: Mamaev Alex , Provatas Nikolas
Published: December 2023

This paper examines the process of nucleation in phase field (PF) models, with the aim of elucidating how the use of diffuse interfaces often employed for quantitative modelling of solidification affects nucleation rates and distribution statistics in relation to the predictions of classical nucleation theory. Nucleation is simulated through the use of noise in a quantitative binary alloy PF model using different interface widths. Our results reveal that the rate of nucleation in the PF model is found to be strongly dependent on the scale of the interface width and the numerical discretization, but that careful control of these quantities offers the possibility of a consistent interpretation of nucleation rate. The paper ends by assessing some of the practical merits of seeded versus noise-induced nucleation in PF modelling in the diffuse-interface limit, while also emphasizing how nucleation in this limit is fundamentally flawed from a quantitative perspective.
A Bayesian statistical method for large-scale MEMS-based sensors calibration: a case study on 100 digital accelerometers
Authors: Prato Andrea , Pennecchi Francesca , Genta Gianfranco , Schiavi Alessandro
Published: December 2023

Low-cost sensors and in particular micro-electro-mechanical systems (MEMS) devices are widely used in many applications, including consumer electronics, healthcare, automotive, and industrial automation. Their large-scale production (typically in the order of millions per week in a single factory) would require the calibration of a huge number of devices that would be costly and time-consuming. A solution can be found in the use of statistical methods in order to (at least partially) substitute for the typical calibration procedures. In this work, we propose a Bayesian method to statistically calibrate large batches of sensors using probabilistic models and prior knowledge. The method involves experimentally calibrating only a small sample of sensors, then infer the number of reliable sensors in the entire batch and assign an appropriate uncertainty to all the sensors. Therefore, it can be considered as a statistical calibration of the batch. The Bayesian nature of this approach allows reducing the number of experimental calibrations by incorporating the prior knowledge coming from the previous calibration of a ‘benchmark’ batch, which is performed ‘once and for all’ and is representative of the whole production process. The application and validation of the method are performed through the calibration of 100 digital MEMS accelerometers. Validation results showed an acceptable agreement between experimental-based bootstrap and theoretical values, with relative differences within ±7%.
Simulation study on high spatio-temporal resolution acousto-electrophysiological neuroimaging
Authors: Schoeters Ruben , Tarnaud Thomas , Martens Luc , Tanghe Emmeric
Published: December 2023

Objective. Acousto-electrophysiological neuroimaging (AENI) is a technique hypothesized to record electrophysiological activity of the brain with millimeter spatial and sub-millisecond temporal resolution. This improvement is obtained by tagging areas with focused ultrasound (fUS). Due to mechanical vibration with respect to the measuring electrodes, the electrical activity of the marked region will be modulated onto the ultrasonic frequency. The region’s electrical activity can subsequently be retrieved via demodulation of the measured signal. In this study, the feasibility of this hypothesized technique is tested. Approach. This is done by calculating the forward electroencephalography response under quasi-static assumptions. The head is simplified as a set of concentric spheres. Two sizes are evaluated representing human and mouse brains. Moreover, feasibility is assessed for wet and dry transcranial, and for cortically placed electrodes. The activity sources are modeled by dipoles, with their current intensity profile drawn from a power-law power spectral density. Results. It is shown that mechanical vibration modulates the endogenous activity onto the ultrasonic frequency. The signal strength depends non-linearly on the alignment between dipole orientation, vibration direction and recording point. The strongest signal is measured when these three dependencies are perfectly aligned. The signal strengths are in the pV-range for a dipole moment of 5 nAm and ultrasonic pressures within Food and Drug Administration (FDA)-limits. The endogenous activity can then be accurately reconstructed via demodulation. Two interference types are investigated: vibrational and static. Depending on the vibrational interference, it is shown that millimeter resolution signal detection is possible also for deep brain regions. Subsequently, successful demodulation depends on the static interference, that at MHz-range has to be sub-picovolt. Significance. Our results show that mechanical vibration is a possible underlying mechanism of acousto-electrophyisological neuroimaging. This paper is a first step towards improved understanding of the conditions under which AENI is feasible.
Statistical field theory of mechanical stresses in Coulomb fluids: general covariant approach vs Noether’s theorem
Authors: Brandyshev Petr E , Budkov Yury A
Published: December 2023

In this paper, we introduce a statistical field theory that describes the macroscopic mechanical forces in inhomogeneous Coulomb fluids. Our approach employs the generalization of Noether’s first theorem for the case of a fluctuating order parameter to calculate the stress tensor for Coulomb fluids. This tensor encompasses the mean-field stress tensor and fluctuation corrections derived through the one-loop approximation. The correction for fluctuations includes a term that accounts for the thermal fluctuations of the local electrostatic potential and field in the vicinity of the mean-field configuration. This correlation stress tensor determines how electrostatic correlation affects local stresses in a nonuniform Coulomb fluid. We also use a previously formulated general covariant methodology (Brandyshev and Budkov 2023 J. Chem. Phys.
158 174114) in conjunction with a functional Legendre transformation method and derive within it the same total stress tensor. We would like to emphasize that our general approaches are applicable not only to Coulomb fluids but also to nonionic simple or complex fluids, for which the field-theoretic Hamiltonian is known as a function of the relevant scalar order parameters.
Fluctuation relation in continuous-time random walks driven by an external field
Authors: Seki Kazuhiko
Published: December 2023

We study a fluctuation relation representing a non-equilibrium equality indicating that the ratio between the distribution of trajectories obtained by exchanging the initial and final positions is characterized by free energy differences for the duration of the trajectories. We examine the fluctuation relation for noninteracting charge carriers driven by an external electric field by using a continuous-time lattice random walk model with a general waiting-time distribution of transitions. The fluctuation relation is obtained regardless of the lattice structure factor or the form of the waiting-time distribution. However, the fluctuation relation is satisfied only after taking the continuum limit in the presence of a reflecting boundary. Moreover, in free space without boundary conditions, exchanging the initial and final positions is equivalent to exchanging the field (or drift) directions. However, we show that the exchanging field (or drift) directions is not relevant for studying the fluctuation relation under the reflecting boundary condition.
Multi-objective Optimization for the Base Lattice Structure of a Small Space Sampling Return Capsule
Authors: Wang Gang , Zhou Yiming , Wang Chunjie , Ma Shengpeng , Ding Jianzhong
Published: December 2023

The space sample-return mission capsule will bear a large landing impact at the moment of landing, so the return capsule structure is required to be the lightest under the premise of ensuring the safety of equipment and sampling samples. In view of the small size, compact layout and high lightweight requirements of the space sample-return mission module, the base lattice structure made of additive materials can achieve better comprehensive performance of landing impact resistance. In this paper, design of experiments (DOE) and surrogate model are used to carry out parameter sensitivity analysis and multi-objective optimization for the base lattice structure of small return capsule landing impact for space sampling. First, the parametric model of the large base lattice of the landing impact dynamics of the return capsule was established. Then, the Latin Hypercube Sampling (LHS) method was used to carry out sensitivity analysis of the lattice structure parameters and identify key factors. Finally, the response surface model was constructed, and the genetic algorithm was used to optimize the lattice structure parameters. The optimal design was obtained. By comparison with the dynamics analysis model, the results of the surrogate model are basically consistent with the dynamic analysis results.
Study of Zero Gravity Unloading Effect of Mechanical Steerable Satellite Antenna
Authors: Xie Zhuo , Hou Guanzhong , Zhao Ying , Kou Mingkun
Published: December 2023

Due to the limitations of self-structure and test conditions, the actual unloading point is difficult to coincide with the theoretical centroids in a mechanically steerable satellite antenna’s ground zero gravity simulation test. There is a residual moment of unloading. Three-axis mechanical steerable antenna was taken as the research object. Based on a suspension system, the static models of antenna unloading under vertical and horizontal deployment modes were established. The general formula of the joint residual moment was derived. The influence of deployment mode on the joint torsional moment under different working stages was studied. The result shows that the joint torque in the horizontal deployment test is much better than that in the vertical deployment test, with low data peaks and good stability. The horizontal deployment test is preferred for the ground test. The method has been successfully applied to the antenna development of multiple satellites. It has practical guidance and application value for subsequent similar antenna unloading scheme designs.
Design of Power Supply for Distributed Aero-engine Intelligent Control System
Authors: Xu Jing , Zhou Jian , Qian Rongrong
Published: December 2023

Compared with centralized power supply system architecture, distributed power supply architecture can better meet the requirements of distributed aero-engine intelligent control systems. The design of distributed power supply topology plays a vitally important role in the distributed power supply system. The paper presents an engineering design method of distributed power supply for the distributed control system in a certain aero-engine. The distributed power supply topology is developed. Based on this topology, the bus voltage level and the current of the distributed intelligent nodes are designed. The optimal selection method of transmission cable types between intelligent nodes is also provided based on the equivalent circuit of a distributed power supply system. The results show that the cable transmission loss and voltage drop meet the design specifications of electrical cable. The proposed distributed power scheme for the distributed engine control system results in minimal modifications, smaller transmission current, and lighter cables.
Integrated design of sun-synchronous orbit and launch vehicle trajectory for operationally responsive space
Authors: He Shaofei , Gu Zhenfeng , Xu Huijuan , Xu Xiao , Xu Xingshun
Published: December 2023

For the operationally responsive space mission with the known launch point and target area, based on the simplified trajectory, the design method of the sun-synchronous orbit is given by the orbit dynamics, considering the mutually constrained relationship between the satellite orbit and the launch vehicle trajectory. Then, with the orbit parameters as the input, the trajectory model obtains the actual trajectory parameters. Considering the error between the actual and simplified trajectory parameters, the actual trajectory parameters are used to correct the simplified trajectory. Finally, by iterative calculation, the parameters of sun-synchronous orbit and launch vehicle trajectory for operationally responsive space are obtained with the finite trajectory error. For a typical example, the parameters are calculated by the method, which is verified by the STK simulation, demonstrating the feasibility and practicability of the method. The design method can provide theoretical support for the orbit and trajectory design of operationally responsive space.
Design of Micro Piezoelectric Stick-Slip Rotating Motor
Authors: Lu Jiangang , Xie Xingyang , Cui Yuguo , Yang Yiling
Published: December 2023

In the article, the design of a piezoelectric stick-slip rotary motor is proposed that can be used as the rotary drive part of a micro-nano operation. First, a force-coupled stator based on a flexible mechanism with a diameter of 23 mm was designed. Based on the designed stator, the structure of the rotary motor is constructed and its motion steps are analyzed. Then, finite element analysis is performed. Finally, the performance of the motor is tested and conclusions are drawn. The simulation and experimental results show that the developed motor performs well.
STTSRL: Design of Triple-Node Upset Self-Recovery Latch Based on Schmidt Trigger
Authors: Zhou Jing , Zhang Jishan , Zheng Chun
Published: December 2023

With the continuous progress of semiconductor technology, the size of transistors has reduced, and the sensitivity of logic circuits to soft errors caused by radiation has enhanced. The multiple-node upset caused by radiation has affected the reliability of the circuit. This paper proposes a triple-node upset (TNU) self-recovery latch based on the Schmidt trigger (ST) for radiation hardness. The feedback loop is formed by connecting C-elements (CEs) and STs. Using the error filtering mechanism of CE and the hysteresis effect of ST is to realize the reliability of STTSRL. Under the 22 nm PTM process in HSPICE simulation, the STTSRL latch has TNU self-recoverability. Compared with the average value of the same recoverability latch proposed previously, the power consumption, delay, area, number of transistors, and PDAP are reduced by 44.85%, 53.32%, 40.34%, 19.24%, and 83.54%, respectively.
Cooperative Path Planning of Ground-air Robots for Distributed Photovoltaic Inspection
Authors: Liao Chuanqi , Liu Zuoshi
Published: December 2023

Facing the Distributed PV generation inspection scenario, to overcome the low efficiency of traditional manual inspection and the insufficient endurance of existing UAV inspection, UAV aerial inspection and UGVs to provide energy supply in the road network are adopted, and a path planning method that prioritizes the meeting points is proposed. Firstly, the improved genetic algorithm is used to plan the inspection path of each UAV, then the UAV path is clustered to determine the optimal number of meeting points, then the adaptive particle swarm algorithm is used to find the best location of the meeting points in the road network, and finally, the patrol path with the meeting points is optimized twice. Through the simulation test of the standard data set and real data, the effectiveness of the proposed method in solving the path planning problem of distributed photovoltaic coordinated inspection by ground-to-air robots is verified.
Design of Conformal Cooling System with Lattice-structure of Mold Based on 3D Printing
Authors: Zhao Caoxi , Chu Zhong , Kang Hui , Ni Zihan , Li Zhitong , Zhang Jicong
Published: December 2023

The conformal cooling water circuit manufactured by using metal 3D printing SLM technology has significant advantages, compared to the straight drilling cooling water circuit, but there is still a problem of large temperature differences in local mold positions. Based on a circular cross-section spiral-shaped waterway, this article proposes a design that replaces a circular cross-section single helix with a runway-shaped double helix structure and sets a lattice structure in areas with large temperature differences. Finally, Moldflow is used to simulate the cooling effects of the two cooling forms. The results show that the lattice structure can significantly improve the phenomenon of uneven cooling, and the surface temperature difference of the mold has been improved by 41%. Compared to the circular section, the runway-shaped section has a better cooling effect, better temperature distribution, and more uniform cooling.
Real-Time Guided Positioning Method of Single-Station Theodolite in Height-Keeping Flight Scene
Authors: Liu Chuanling , Zhao Ke , Fu Feiya , Lei Hao
Published: December 2023

The photoelectric theodolite of high precision without laser ranging system has been frequently used in the actual exterior ballistics test of conventional weapons to complete the testing task. In the specific test section, there has been only one theodolite tracking the target or multiple theodolites tracking but can’t meet the intersection conditions, which can’t provide guidance data for other stations, leading to testing task failure. To improve the ability to complete the tasks successfully, a real-time guided positioning method of single-station theodolite is proposed for the special test scene of the height-keeping flight target. The accuracy estimation model is established according to the mathematical model of line-surface intersection. The simulation experiment verification and practical application effect show that our method can meet the accuracy requirement of real-time guidance in the shooting range so that the reliability of this test task can be improved and the guidance mode of external measurement in the shooting range can be enriched.
Research on chamfer structure effects for the microforce measuring device output
Authors: Li Chuang , Hu Lihong , Li Qian , Xu Li , Wang Shuxiang
Published: December 2023

The influence of chamfer structure on microforce measuring device output has been researched by theoretical calculation and numerical simulation. The relationship between the chamfer dimensions and the microforce output was analysed under different parameters such as electrode intersection length and electrode spacing. Based on the analysis of the electric field distribution of the capacitive microforce device, the mechanism of improving the device output performance with chamfer had been obtained. The results show that the influence of the chamfer was not obvious when the electrode gap was large. With the decrease in the electrode gap, the chamfer could effectively improve the electric field distribution between the electrodes, so as to form a section insensitive to the electrode intersection length. In this region, even if the intersection length changed greatly, the device could still produce a very stable microforce. This research could be used as a guide to improve the accuracy and stability of microforce measuring devices.
Analysis of Error Sources of a Torque and Rotation Angle Calibration Unit Based on Statics
Authors: Zhao Jiliang , Wang Liyang , Shou Junming , Shi Hailin , Gu Jiajun , Yang Mei , Li Hongbo , Li Guanren , Xiong Wanzhong
Published: December 2023

The structure and working principle of the torque calibration unit, the index angle calibration unit, and the loading mechanism are introduced. Using finite element analysis tools for static analysis, the error sources of the calibration process are obtained and the influence on the calibration results is analyzed. Among them, the influence of connecting rod deformation, torque transmission characteristics, and flexible deformation on the calibration accuracy is small and can be ignored. Bearing friction, coaxiality, and micro-deformation of the test bench are inherent errors of the system. For its own inherent error attribute, it will not affect the relationship between the sensor to be calibrated and the standard sensor on the output shaft of the index test bench, that is, it will not affect the calibration process of the sensor to be calibrated later.
Research on Electronic Differential Steering Control Strategy for Aircraft Electric Tractors
Authors: Gao Jianshu , Jing Cao
Published: December 2023

Compared with the traditional fuel aircraft tractor, the electric tractor using the four-wheel hub motor independent drive mode has the advantages of environmental protection, low costs, flexibility, high controllability, and convenience for later maintenance. The paper uses a four-wheel hub motor tractor and a linear vehicle model to propose a hierarchical steering control strategy. The upper layer control adopts the improved integrated sliding mode control algorithm with the yaw angular speed as the control goal to obtain the additional yaw torque. The additional yaw torque obtained is reasonably distributed to each wheel by the use of the rule distribution algorithm of the lower layer control, to obtain the optimal driving torque of each wheel. Finally, the steering stability of the electric aircraft tractor at different speeds is verified based on Simulink. The results show that the control strategy can better control the speed and stability of steering control of electric vehicles.
Aeroacoustic Analysis of Rapid Position Changing Process of Missile Seeker Equipment
Authors: Wang Yanqing , Kang Wei , Hu Shilin
Published: December 2023

A two-dimensional CFD model of the rapid position-changing of missile seeker equipment is presented to study its aeroacoustic impact. By combining the computational fluid dynamics (CFD) with the Ffowcs Williams-Hawkings (FW-H) equation, the flow and related aeroacoustic features are analyzed under different flight Mach numbers and flight heights. The impact of seeker movement on the flow field and aerodynamic noise are highlighted. The results indicate that the spectrum peak of sound pressure level increases with the vortex shedding frequency as the flight Mach number increases. As the flight height of the missile increases, the sound pressure level is amplified while the frequency of vortex shedding decreases.
Slat Control Asymmetry Failure Simulation and Research
Authors: Ma Yuan
Published: December 2023

To construct the slats control system model and design asymmetry failure injection in the Slats control model, this paper provides an operation analysis of Slat system control and mechanical actuation in detail. The model of a slat control system based on Matlab or Simulink is established. Also, the method of slat asymmetry failure injection is designed, the root cause of slat asymmetry failure is listed, and left slat asymmetry failure is simulated via the designed model. The results demonstrated that the slats control system model and failure injection method can support the simulation of slat asymmetry failure and established the basis for subsequent research on the slats control system.
Fault Diagnosis of Rotating Machinery under Complex Conditions Based on Multi-Scale Convolutional Neural Networks
Authors: Kang Jing , Luo Yuting , Wang Peng , Wei Ye , Zhou Yiren
Published: December 2023

In complex operational scenarios involving variable speeds, burdens, and noise, rotating machinery necessitates extended maintenance. Extracting stable and effective fault-sensitive features under such intricate conditions presents a significant challenge. To tackle this issue, the paper introduces the Multi-Scale Convolutional Neural Network (MSCNN) model tailored specifically for such complexities. The approach in this paper simultaneously captures multi-scale vibration signal features using the innovative Multi-Scale Bifurcation (MSB) module and subsequently aggregates them through a multi-scale fusion layer. This model effectively addresses the common problem of low CNN accuracy in fault diagnosis. The paper validates methodology using a bearing dataset provided by Case Western Reserve University (CWRU) and demonstrates superior performance compared to classical CNN models and other alternatives, achieving an impressive 99.56% classification accuracy for normal signals.
Research on the influence of time delay on combat effectiveness of aircraft fleet
Authors: Ye Haijun , Li Meihong , Yang Zhe
Published: December 2023

Aiming at the influence of time delay on the combat effectiveness of aircraft fleet under the command of airborne warning and control system (AWACS), the process of beyond visual range air combat under the command of AWACS is analyzed, as well as the time delay characteristics in the combat information flow. The air combat situation threat of the aircraft by enemy aircraft is represented by the weighted fusion of the speed threat, angle threat, distance threat, and height threat of the aircraft. The threat matrix is proposed to represent the threat to the whole aircraft fleet. The threat matrix consists of the situational threat between each of our aircraft and each of the enemy aircraft. And the threat matrix of both sides is calculated to obtain the pre-enemy launch probability of both sides. With the two-step adjudication method and capturing the target probability of the missile seeker under the influence of time delay, the probability and number of being destroyed are calculated, as well as the combat effectiveness ratio. The opposing forces of both sides are set, and the calculation results in Matlab are consistent with the actual ones, which verifies the rationality and validity of the model, and can provide a theoretical reference for determining the time accuracy of the air-based network.
A Threshold Design Method of Aircraft Sensor Fault Detection Monitor
Authors: Yang Xiaxie , Xue Ying
Published: December 2023

A design method is proposed based on probability and statistics to solve the issue that the contradiction between false alarm rate and missed detection rate of sensor comparing monitor threshold definition. The sensor tracking error probability density function is deduced based on the probability, the false alarm rate and missed detection rate are calculated based on the different monitor threshold. Then a criterion is provided in according with sensor failure rate, aircraft dispatch reliability and monitor failure rate. In order to verify it, a quad redundant rate gyro used on aircraft is analysed and an advanced comparing monitor threshold is calculated. Comparing with the original threshold, the monitor coverage rate with the new threshold is increased 1.42 times than the original one. The actual flight date is researched to verify that the monitor failure rate reach to the minimum value 3.91*10-07/Fh which decrease one order of magnitude comparing with the original one 3.5*10-06/Fh. It could be verified that this method could achieve the balance between the safety and dispatch reliability requirement.
A High Lift Test System Based on Wing Deformation
Authors: Li Aixian
Published: December 2023

In the existing ground verification test of the high lift system, the flap and slat support structure and transmission system support structure are firmly connected with the fixed test platform, which cannot simulate the effect of real wing deformation on the high lift system. In this paper, a series of lifting devices are used to replace the flap and slat structure and transmission shaft mounting surface on the real wing. Through the position control of the lifting devices, the position change of the mounting surface can be realized, which can better simulate the influence of the real wing deformation on the high lift system.
Research on key technologies of scaled model flight testing
Authors: Kong Chuihuan , Pan Lijun , Wu Dawei , Ma Rubing , Cheng Changfu , Lou Yunwen
Published: December 2023

The scaled model flight test is one of the three major technical paths of aerodynamic research, which can be used to study and verify the aerodynamic characteristics, danger boundary, new layout, and new technology of the prototype, with the advantages of short cycle, lower risk, and lower cost. Due to different experimental research purposes, there are different design ideas and schemes for scaled models. With the technological development of power systems such as microturbine engines and electric ducted fans, the scaled model has experienced the stages of non-powered drop flight, rocket-assisted flight, and power-driven free flight. In this paper, two scaled verification models are introduced, the similarity criteria of the scaled model are analyzed, the selection of micro engine is carried out, the ground test methods such as fuel consumption test and moment of inertia test are summarized, some test subjects and results are presented, and the key technologies of the flight test of the scaled model are summarized. The flight test results show that the test method can accurately reflect the aerodynamic characteristics and flight performance of the prototype.
Online evaluation method of resistance spot welding quality based on locally linear embedding algorithm
Authors: Zhou You , Pan Chunrong , Chen Junjie , Gan Yufeng , Gao Xiangdong
Published: December 2023

To address issues of low efficiency, poor feedback timeliness, and unsuitability for fast-paced, high-volume manufacturing of the traditional quality inspection methods of resistance spot welding, an online evaluation method of resistance spot welding quality based on a locally linear embedding algorithm is studied for mild steel resistance spot welding to achieve cost reduction and efficiency improvement. During welding tests, voltage and current were simultaneously collected to calculate the welding power signal. We study the variation pattern of the dynamic power curve. The dynamic power signal was subjected to locally linear embedding and manual feature extraction. The collected features were then used as input to build random forest models and CatBoost models for the online weld quality evaluation, respectively. The results show that the classification models with the feature volumes constructed by locally linear embedding as input have higher assessment accuracy than manually extracted features. The locally linear embedding method can effectively eliminate the subjective influence brought by manual extraction and has better reliability. The CatBoost model based on the locally linear embedding method using the welding power signal can quickly and effectively achieve online quality assessment of mild steel spot welding, providing a further breakthrough in spot welding quality evaluation technology.
Trade Study of Engine Installation Position for a Rear-mount Aircraft
Authors: Chai Xiao , Si Jiangtao , Liu Kaili , Zhong Yuan
Published: December 2023

The meticulous analysis of large bypass ratio engine installation constitutes a vital foundation for the integrated design of civil aircraft engines. To holistically evaluate the performance implications between the engine and the airframe, a trade design concerning the engine installation position for a rear-mounted regional aircraft is conducted by utilizing computational fluid dynamics, incorporating a powered nacelle to account for the engine’s intake and exhaust ramifications. The engine’s longitudinal, spanwise, and vertical positioning impacts on aircraft drag and installed net thrust were discerned. The nacelle’s longitudinal displacement exerts the most substantial influence on the aggregate aircraft gain. The optimal configuration, achieved by advancing the engine 500 millimeters forward, yields a drag advantage of 2.24 counts and a thrust augmentation of 0.49 counts, culminating in a combined gain of 2.73 counts.
Considering lateral bending and torsion coupling in shimmy analysis of the nose landing gear
Authors: Zhang Peng , Zhu Dabin , Dong Huli , Wang Zeng , Wang Jiaao , Chen Xiying
Published: December 2023

This paper focuses on the shimmy damper performance of nose landing gear and aims to establish and amend a five-dimensional dynamic model of nose landing gear. The study compares the shimmy damper performance of nose landing gear whether considering lateral bending and torsional vibrations coupling and concludes that the amended model provides greater accuracy. In addition, the research compares the shimmy performance of passive and active shimmy dampers, finding that the active shimmy damper significantly outperforms the passive one in terms of efficiency. The amended model is also shown to improve the shimmy damper performance of active shimmy damper.
Research of test method for ski-jump takeoff which is based on BP neural network and multi-factor weight analysis
Authors: Liu Miaoxin , Yuan Zhengting , Liu Tao
Published: December 2023

Ski-jump takeoff of carrier-based aircraft is a very risky subject. At present, the principle, characteristics and influencing factors of ski-jump takeoff are mainly studied at home and abroad, but there is no relevant research on how to carry out ski-jump takeoff test and related risk control. To ensure smooth and safe ski-jump takeoff testing, this paper first determines the influencing factors of ski-jump takeoff based on the dynamics model. Secondly, based on the BP neural network, the corresponding relationship between the influencing factors, the angle of attack and the lifting speed is established. Finally, the quantitative analysis conclusion of the influencing factors is obtained according to the multi-factor weight analysis method and put forward the design method takeoff under the combined conditions of “weight-center of gravity-inertia-configuration” and the test risk control measures, which provides methods and ideas for the safety of ski-jump takeoff test.
Safety analysis of catapult takeoff of carrier-based aircraft using System-Theoretic Process Analysis method
Authors: Liu Tao , Liu Miaoxin , Jiao Xiaohui
Published: December 2023

Catapult takeoff has become the main way for carrier-based aircraft to take off. However, as a complex process of multi-system coupling and multi-control actions link, it is an important task to ensure the safety of catapult takeoff. Therefore, this paper adopts the System-Theoretic Process Analysis (STPA) and establishes a model of catapult takeoff using the Systems Theoretic Accident Model and Process(STAMP) model. To carry out safety analysis, identify unsafe control actions and extract the causes of unsafe behavior, simulation analysis is also carried out for typical unsafe actions. The results show that using STPA to make safety analysis, combined with simulation, can comprehensively analyze and evaluate the safety of catapult takeoff, which helps identify the risk before the flight test and reduce the flight test risk.
Engineering evaluation method for adaptability of SRM to low-temperature operation
Authors: Li Yuan , Ma Liang , Fu Dongsheng , Luo Jingqi
Published: December 2023

In view of the adaptability of the solid rocket motor (SRM) to work at low temperatures, an engineering evaluation method is proposed. A test method that can characterize the low-temperature ignition bearing capacity of the SRM is designed and put forward. At the same time, a comprehensive evaluation method for the adaptability of the SRM to work at low temperatures is proposed. It is combined with the numerical simulation analysis of the structural integrity of the SRM grain. The evaluation results obtained by this method are in good agreement with the SRM low-temperature test results. It can provide a basis for the reliability design and engineering development of the SRM low-temperature operation.
Two-stage calculation model of single pulse vehicle tracking target and flight track
Authors: Yang Ling , Mao Dejun , Wang Wenqiang
Published: December 2023

In order to get rid of the tracking of single-pulse guided aircraft, it is necessary to study its guidance method, analyze its flight and speed change laws, and deeply understand its performance. In this paper, the guided aircraft using the single-pulse working mechanism is analyzed from the flight speed change, the speed and distance changes in the flight process with time are analyzed, and the approximate calculation model is established, which is of good help for understanding the flight process of the single-pulse vehicle.
Modeling and Simulation of the Stepping Motor Operation Curve
Authors: Che Xing-bang , Zeng Hui , Zhou Kai , Xiao Han , Wang Xu-wen , Wu Xu , Li Chun-bo
Published: December 2023

To improve the open-loop control performance of stepper motors, research was conducted on their operating curves. The acceleration-velocity characteristic equations of three common operating curves were established and compared with the torque frequency characteristic curves of stepper motors. Based on this, an improved segmented correction fitting S-shaped (SCFS) curve design method based on a high torque utilization sine curve was proposed to solve the problem of rotor blockage and overshoot caused by uneven acceleration during the operation of stepper motors. In the simulation of the stepper motor load motion system, the SCFS curve was compared with common curves. The simulation results showed that the position tracking error was reduced by approximately 82% compared to the trapezoidal curve and approximately 70% compared to the exponential curve. Research has found that this method is suitable for the design of high-precision motor operating curves and has a high application value in the field of precision motion control.
Synthesis, structure, and photoluminescence analysis of thermally stable Sm3+ doped YPO4 phosphor
Authors: Kumar Ishant , Kumar Avinash , Kumar Sandeep , Thakur Himani , Gathania Arvind K.
Published: December 2023

In this manuscript, we used the coprecipitation method to manufacture Sm3+ doped YPO4. To verify the phase and structural properties of the synthesized material, we performed XRD. The diffraction patterns of the synthesized sample match the tetragonal YPO4 with no indication of an impurity peak, demonstrating the creation of a pure phase. The photoluminescence excitation and emission profiles of the synthesized material were recorded. Characteristic excitation and emission peaks of Sm3+ were observed. The distinctive orange-reddish emission of Sm3+ is found at the highest intense excitation peak (404 nm). The CIE spectral coordinates of the phosphor are (0.6080,0.3912). The emission spectra are recorded under various excitation levels. The temperature-dependent emission under 404 nm excitation is also observed to confirm the thermal stability of the synthesized material. The emission intensity drops just 13% up to 150 °C, indicating the material’s remarkable thermal stability. These findings indicate that the synthesized material is suitable for application in display devices.
Influence of Mg doping on the structural and optical properties of manganese oxide (Mn2O3) nanoparticles
Authors: Singla Samiksha , Kalra Diksha , saini Aditi , Anand Krishma , Tripathi S.K.
Published: December 2023

The work presents here the synthesis of pristine manganese oxide (Mn2O3) nanoparticles and magnesium (Mg) doped Mn2O3nanoparticles with the help of the chemical co-precipitation method. We have investigated the influence of Mg doping (9 wt%, 12 wt%, and 15 wt%) on the optical and structural properties of Mn2O3. The structural properties of undoped and doped Mn2O3 nanoparticles have been studied using X-ray Diffraction Spectroscopy (XRD). The numerous physiochemical bondings present within the prepared nanoparticles have been examined using Fourier Transform Infrared Spectroscopy (FTIR). Both photoluminescence (PL) and UV-Visible (UV-Vis) spectroscopy have been used to investigate the optical characteristics. All the measurements are done at room temperature. All of the samples’ absorption spectra have been investigated within the wavelength range of 200 to 800 nm. The UV-Vis absorption spectrum for pristine Mn2O3 nanoparticles shows a sharp peak at 289 nm. We have further determined the band gap of the prepared samples using Tauc’s equation. The pristine Mn2O3 exhibits a direct bandgap of 4.04eV. At an excitation wavelength of 320 nm, the prepared samples’ emission spectra have also been recorded.
Enhancement of photocatalytic activity in SrTiO3 with doping of MgO nanoparticles
Authors: Maurya Archna , Kaur Rajveer , Ghumman S S
Published: December 2023

In recent years, photocatalytic activity (PA) using semiconductor nanoparticles has gained attention, especially with titanium dioxide (TiO2) due to its broad activity spectrum [1-2]. There are several applications for this technique, including the purification of water, control of air pollution, and soil gradation. In the present study, trace amounts of magnesium oxide nanoparticles (MgONPs) have been doped in SrTiO3 ceramics to enhance PA. The MgONPs have been prepared using the sol-gel auto-combustion method during continuous stirring while heating at 70°C and in neutral conditions (pH=7.0). The MgONPs doped SrTiO3 ceramics with compositions of Sr1-xMgxTiO3 (x = 0.05, 0.1, and 0.15) have been synthesized by two-stage solid-state reaction at 900°C calcination and 1200°C sintering temperatures. Analyses of the samples are in progress using EDS, FESEM, XRD, and UV-visible techniques to identify the effects of doping on the structure of the samples.
Efficiency of Prevention of Biofilm Formation by Modified Polyurethane Nanofibers in Different Bacterial Strains
Authors: Khan Rumysa S , Rather Anjum H , Wani Taha U , Rafiq Muheeb , Sheikh Faheem A
Published: December 2023

In tissue engineering biofilm formation is a major concern where bacteria form biofilms over the implants, devices or tissue scaffolds. To prevent this biofilm formation an attempt has been made in this study by using a modified nanofiber fabricated from a polymer incorporated with an antibacterial agent. Polyurethane (PU) nanofibers provide a high surface area for efficient substance delivery within a biological surface. In this paper β-cyclodextrin (CD) incorporated PU nanofibers were fabricated by electrospinning. CD was added to impart hydrophilicity to the nanofiber mat. For the antibacterial activity silver nanoparticles (Ag NPs) have been used. In this study Ag NPs have been incorporated in the composite scaffolds by two methods, viz, physical adsorption and hydrothermal adsorption. Scanning electron microscopy showed the smooth and bead-free morphology of nanofibers. The contact angle analysis showed the lowered contact angle in case of nanofibers containing CD and Ag NPs which confirmed the increased hydrophilicity by CD. The Ag release assay showed the different release profiles in two types of composites. Ag was released slowly in case of the composite where Ag had adsorbed firmly to the nanofibers as compared to the composite where Ag was adsorbed loosely. The disc diffusion assay showed the growth inhibition of different bacterial gram-positive and gram-negative strains by the composite scaffolds. The in-vitro cell viability assay showed the cells were viable on these composites and these were usable for biological applications. This study suggests a new way of biofilm prevention using PU nanofibers.
Modification of hydrophobic electrospun polyurethane fibers for efficient wound healing activity
Authors: Rather Anjum H , Khan Rumysa S , Rafiq Muheeb , Wani Taha U , Sheikh Faheem A
Published: December 2023

The intricate process of wound healing demands an atmosphere that is conducive to quick healing. In this situation, creating biocompatible and antibacterial fibers may be a good choice. In this study, the unmodified polyurethane and polyurethane modified with cellulose acetate and rosemary oil were electrospun into fibers. These fibers were subsequently adsorbed using silver nanoparticles. The FE-SEM was used to characterize the fibers, revealing their defect-free morphology and the presence of nanoparticles on them. Additionally, the XRD findings demonstrated that silver nanoparticles were successfully incorporated into the spun fiber mats. The contact angle measurements indicated a decreasing behavior starting from 100.4±1° to 28.4±3° in the case of unmodified polyurethane and modified fibers. The antibacterial assay revealed that although unmodified fiber mats have negligible antibacterial action, the modified fibers exhibited considerable antibacterial activity against E. coli and S. aureus. In-vitro studies revealed that Human embryonic kidney 293T (HEK 293T) cell proliferation was enhanced on the surface of modified fibers compared to unmodified fibers. In conclusion, our research presents unique multifunctional fibrous scaffolds that are appropriate and optimal for wound healing applications.