bluuebunny/crossref_metadata_2025_split huggingface dataset:
High surface quality heteroepitaxy α-Ga2O3 film on sapphire by mist-CVD technique
Authors: Li Xiongjie , Niu Pingjuan , Ning Pingfan , Jiang Yong 
Published: May 2023

Abstract
An ultra-flat heteroepitaxy α-Ga2O3 thin film, paved a glory future for device fabrication, was successfully obtained on a c-plane sapphire substrate through the employment of the mist chemical vapor deposition technique. Atomic force microscopy measurements revealed an root mean square (RMS) roughness value of 0.309 nm when the carrier gas flow rate was set at 1500 sccm. Furthermore, the full-width at half maximum of the rocking curve was determined to be 43.2 arcsec, indicating a high level of crystallinity in the heteroepitaxy film. The growth rate was calculated as 13.22 nm min−1 through the use of cross-section scanning electron microscope measurements. Additionally, the bandgap of the transparent film was determined to be 5.10 eV through transmittance spectra analysis. The high quality, wide bandgap heteroepitaxy α-Ga2O3 thin film described in this study represents a significant step forward in the preparation of high power and optoelectronic devices.
Comparative study of multilayered graphene using numerical descriptors through M-polynomial
Authors: M C Shanmukha , A Usha , N S Basavarajappa , K C Shilpa 
Published: May 2023

Abstract
Molecular descriptors play a powerful role in encoding the information of a chemical compound using its molecular structure based on a defined algorithm. Regardless of the evolution in drug design, the main tool used in discovering the lead molecules of a drug refers to the use of topological descriptors. This article focusses on M-polynomial of multilayered graphene, viz., monolayer, bilayer and trilayer. Using the M-polynomial, eleven degree-based topological indices are derived for the said three structures. 3D-plot of the polynomials shows variation among the three types of graphene. The numerical and graphical comparison of the indices for varying values of n are tabulated for better understanding.
The First Photometric and Spectroscopic Studies of ASASSN-V J015428.67+204247.2 and its Relation to the Population of Low Mass Ratio Contact Binaries
Authors: Li Ke-Xin , Li Kai , Liu Fei , Gao Xing , Sun Guo-You , Wang Xi , Yin Shi-Peng 
Published: May 2023

Abstract
We performed photometric, spectroscopic and orbital period investigations of ASASSN-V J015428.67+204247.2 (hereafter, J015428) for the first time. The light curves of VRI bands were obtained. Through the analysis of Wilson–Devinney program, J015428 was found as an A-subtype medium contact binary system with a low-mass ratio (q = 0.129, f = 26.8%). The atmospheric parameters were determined in spectroscopic analysis. In the orbital period investigations, we found that the orbital period of J015428 decreases at the rate of −7.13 × 10−8 day yr−1. And the long-term orbital period decrease is possibly due to angular momentum loss (AML). The absolute parameters was calculated with the photometric solutions and Gaia distance. Through the analyses of mass–radius and mass–luminosity diagrams of 54 contact binaries with the low mass ratios (0.096 ≤ q ≤ 0.15), the evolutionary states of low mass ratio binaries were investigated. The results by analyzing the energy transfer parameter indicated that energy transfer rate was a function of mass and bolometric luminosity ratio. We estimated the initial masses and the densities of two components and the age of the binary. The analysis of the orbital angular momentum supposed that J015428 may evolved from a short-period detached binary by AML. J015428 is in a stable contact stage at present.
Identifying ADHD boys by very-low frequency prefrontal fNIRS fluctuations during a rhythmic mental arithmetic task
Authors: Ortuño-Miró Sergio , Molina-Rodríguez Sergio , Belmonte Carlos , Ibañez-Ballesteros Joaquín 
Published: May 2023

Abstract

Objective. Computer-aided diagnosis of attention-deficit/hyperactivity disorder (ADHD) aims to provide useful adjunctive indicators to support more accurate and cost-effective clinical decisions. Deep- and machine-learning (ML) techniques are increasingly used to identify neuroimaging-based features for objective assessment of ADHD. Despite promising results in diagnostic prediction, substantial barriers still hamper the translation of the research into daily clinic. Few studies have focused on functional near-infrared spectroscopy (fNIRS) data to discriminate ADHD condition at the individual level. This work aims to develop an fNIRS-based methodological approach for effective identification of ADHD boys via technically feasible and explainable methods. Approach. fNIRS signals recorded from superficial and deep tissue layers of the forehead were collected from 15 clinically referred ADHD boys (average age 11.9 years) and 15 non-ADHD controls during the execution of a rhythmic mental arithmetic task. Synchronization measures in the time-frequency plane were computed to find frequency-specific oscillatory patterns maximally representative of the ADHD or control group. Time series distance-based features were fed into four popular ML linear models (support vector machine, logistic regression (LR), discriminant analysis and naïve Bayes) for binary classification. A ‘sequential forward floating selection’ wrapper algorithm was adapted to pick out the most discriminative features. Classifiers performance was evaluated through five-fold and leave-one-out cross-validation (CV) and statistical significance by non-parametric resampling procedures. Main results. LR and linear discriminant analysis achieved accuracy, sensitivity and specificity scores of near 100% (p <.001) for both CV schemes when trained with only three key wrapper-selected features, arising from surface and deep oscillatory components of very low frequency. Significance. We provide preliminary evidence that very-low frequency fNIRS fluctuations induced/modulated by a rhythmic mental task accurately differentiate ADHD boys from non-ADHD controls, outperforming other similar studies. The proposed approach holds promise for finding functional biomarkers reliable and interpretable enough to inform clinical practice.
Study on KIC of TC4-DT titanium alloy electron beam welding
Authors: Xianglin Ye , Yuchun Feng , Jiawen Wang , Linyun Shang 
Published: May 2023

Abstract
With the development and application of TC4-DT titanium alloy and electron beam welding, the research on fatigue crack growth of its joints is very important in engineering. In this paper, the relevant fracture mechanics and crack growth theory are proposed for the fatigue crack growth of TC4-DT titanium alloy electron beam welded joints, and the experimental and finite element method simulation crack growth research is carried out. The results show that: during the fatigue crack test, with the continuous increase of the cycle period, the crack growth rate in different regions increases significantly, among which the growth rate of the weld zone is higher, and the crack propagation path in the weld zone is almost completely along the weld zone. The direction of the axis of symmetry of the center of the crack propagates linearly, and the crack propagation in the base metal area basically expands along the straight line but slightly deviates to the upper base metal area. By calculating the stress intensity factor of different preset crack lengths through simulation, it is found that within the allowable error range, with the increase of the prefabricated crack length, the stress intensity factor k1 of the specimen increases gradually.
Numerical analysis of fuel regression rate and flow field in solid fuel ramjet with the gas generator
Authors: Lu Xuancheng , Zhou Changsheng , Wang Luhao , Zhu Min 
Published: May 2023

Abstract
In this paper, to improve the combustion characteristics and working performance of the solid fuel ramjet, a solid fuel ramjet with a gas generator is proposed. Based on k − ω SST and Eddy-Dissipation equations, the turbulent combustion model is established, and the internal flow field of the ramjet, as well as the regression rate, and species, were numerically analyzed. The results show that the temperature of the ramjet and the regression rate with a gas generator is increased. When the airflow is 0.4kg/s, the increase of the gas generator flow will lead to a more obvious regression rate increase, and the maximum value will increase by 33%. When the airflow is 0.6kg/s, the regression rate with the gas generator is evenly distributed along the axis. The flame with a gas generator makes the head burn more completely, the combustion chamber temperature increases, and the average regression rate of solid fuel increases by 14%.
Fatigue life prediction of aircraft gun cabin structure under impact
Authors: Ding Zhenhao , Wang Ke 
Published: May 2023

Abstract
The aircraft gun firing will cause serious impact on airframe structure. According to the gun firing principle, the muzzle blast wave is simulated by chemical explosion. ALE method is used to deal with the fluid-structure interaction between high-pressure flowing air and the surface of the cabin. Then the expression model of the impact load is established. The numerical calculation is completed to analyse the dynamic response of the cabin structure under the impact load. The parameters of load and cabin model are modified by using the experiment results. Comparing the calculated dynamic response with the experiment results, the error is within acceptable range. Multiaxial stress equivalence and rain-flow counting method are used to process the simulation impact response data to estimate the impact fatigue life. In conclusion, the paper provides a feasible method for analysing dynamic response and fatigue life of gun cabin structure.
Prediction model of GEO spacecraft position after maneuver based on causal Bayesian network
Authors: Long X , Yang L P , Chen S Y , Xu S 
Published: May 2023

Abstract
Predicting the position of Geosynchronous (GEO) spacecraft under maneuver is a crucial work for space domain awareness (SDA) as it can help to improve the flexibility and operational efficiency of space surveillance network (SSN). The longitude is a unique freely assigned parameter for GEO spacecraft, in this paper, a predictive model of GEO spacecraft longitude based on causal Bayesian network is proposed. Firstly, the causal parameters of longitude is found by Gaussian perturbation equation. Secondly, the Markov order of the causal parameters is obtained by transfer entropy. Finally, the linear expressions for Gaussian functions is proved and a causal Bayesian network (CBN) prediction model for longitude is constructed. After experimental analysis, the mean absolute error (MAE) and mean square error (MSE) of the proposed method are decreased by 71.88% and 72.18%, respectively compared with the traditional Long short-term memory (LSTM) method.
Adaptive attitude control of UAV based on neural network compensation
Authors: Li Yihang , Lei Zhongkui , Guo Yueru , Chen Kuiyu , Jin Jie , Yang Yixin 
Published: May 2023

Abstract
Aiming at the problem of unmanned aerial vehicle (UAV) attitude control with insufficient robustness and anti-disturbance, this paper proposes a UAV attitude control method combining incremental nonlinear dynamic inverse (INDI) and neural network (NN) adaptive compensation. Firstly, the attitude model of UAV with time scale separation is proposed. On this basis, the INDI control law is derived, and the angular acceleration information required by INDI method is feedback by the filter. Then, the adaptive NN compensation structure is introduced to eliminate the uncertainty caused by model mismatch, sensor delay and external disturbance. Finally, the UAV simulation is carried out. The result shows that this method improves robustness and anti-disturbance of original INDI method without changing structure and parameters of controller, and has a certain adaptive compensation ability for system uncertainty.
Efficiency analysis of intercepting UAV swarm by various air defense methods
Authors: Hu S G , Ru L , Lu B , Wang W F 
Published: May 2023

Abstract
In order to accurately intercept incoming swarm targets and improve interception efficiency, the interception efficiency of various air defense equipment was studied. The paper introduces the current ways to deal with the UAV swarm, and establishes the mathematical model of different types of interception equipment; Under the premise of given interception probability, the time and cost of different interception methods are calculated respectively, and the weight distribution is used to analyze the interception efficiency of different weapons. According to the analysis process and results, the interception effectiveness of different weapons is sorted. The analysis results show that the analysis has certain practicability, which can support the development and application of air defense interception weapons and equipment to a certain extent, and has practical reference value and significance.
Thermal design and analysis of JZJ-5 CubeSat
Authors: Zhou Yudong , Zhang Xiang , Xu Chang , Yang Xudong 
Published: May 2023

Abstract
JZJ-5 is a 3U commercial CubeSat contracted by Nanjing University of Science and Technology. This paper first introduces the thermal control design of the CubeSat, then calculates the temperature field in the high and low temperature conditions by using the finite element method, and finally compares the measured temperature data in orbit with the thermal simulation data. The data results show that the temperature state of the CubeSat in orbit meets the requirements of thermal design, and the thermal control design scheme and simulation model are reasonable.
Experimental research on effect of zonal heating airfoil about boundary layer flow and heat transfer
Authors: Dong Meijuan , Sang Weimin , Yang Guangjun , Jiang Feng 
Published: May 2023

Abstract
The anti-icing of aircraft and large wind turbines, where the wall temperature is higher than the fluid temperature, can significantly alter the flow evolution characteristics of the boundary layer. Local heating strategies for the manifold state need to be designed based on the changing characteristics of the flow velocity and temperature field in order to precisely control the heat supply and reduce inefficient energy consumption. In order to obtain accurate heat transfer characteristics of the airfoil’s boundary layer flow, it is necessary to refine the measurement of the boundary layer characteristics during flow and heat transfer. In this paper, wind tunnel experiments are carried out on the NACA2412 model with full surface’s zonal electric heating. The wall surface is equipped with a built-in heater and the temperature of the wall surface is obtained through the corresponding temperature sensor. By studying layer characteristics of the four heated regions, namely the laminar flow region near leading edge, the laminar flow destabilisation region, the transition region and the fully turbulent flow region, and comparing them with the boundary layer characteristics of the unheated airfoil, the effects of the presence of heat sources in different regions on the stability of the flow field and the spatial heat transfer pattern are revealed. The results show that heating in the laminar and turbulent zones maintains the stability of the flow field to a greater extent and achieves better heat transfer strength, while heating in the unstable zone brings forward the turbulence and heating in the fully turbulent zone intensifies the flow separation at the trailing edge of the airfoil. This study can be used as a reference for the design of efficient anti-icing systems on full wing surfaces.
Multivariable steady-state control of variable cycle engine based on LQG/LTR
Authors: Dong Yunhui , Guo Yingqing , He Jiale , Guo Pengfei , Zhao Wanli 
Published: May 2023

Abstract
In order to improve the steady-state control performance of variable cycle engine, a steady-state multivariable control method based on LQG/LTR is proposed in this paper. The working characteristics and control laws of variable cycle engine are analyzed, and the linearized model of engine design point is obtained by system identification. Based on the LQG/LTR control method and the linear model, a multivariable steady-state controller for the variable cycle engine is designed. Through simulation verification and comparison with the control performance of the three-loop univariate PI controller, it is concluded that the multivariable LQG/LTR controller has excellent disturbance suppression and command tracking ability, and has a wider application range and better control effect than PI controller.
Aerodynamic design of wind turbine blade with second derivative of thickness distribution as constraint
Authors: Xu Jianhua , Zhang Shiqiang , Song Wenping , Han Zhonghua , Zhou Shaojun , Li Xinlong 
Published: May 2023

Abstract
In order to make more use of wind energy, large-scale wind turbine blade size is the trend of development. With the increasing of blade length, the design and manufacture of the structure with the requirements of safety and economy are faced with great challenges. It is most sensitive to the blade manufacturer to reduce the composite lamination and production cost as long as the stress and strain level of the structure is satisfied. Therefore, the ideal thickness distribution requires not only the thickness monotonically decrease along the radial direction, but also the concavity and convexity of the thickness distribution function are required to be constant. Based on the in-house design code SurroOpt and the momentum-blade theory method, an optimization design platform for wind turbine blades was established. A 400kW wind turbine blade design was carried out with the aim of maximizing the output power and the constraint of the second derivative of the thickness distribution. The results show that the concave-convex characteristic of thickness distribution function has not changed, which is beneficial to the structural design. The designed blades have been manufactured and installed for operation. For the whole device, the maximum coefficient of wind energy utilization (including the loss of motor and machinery) reaches 0.42, which is 2.4% higher than 0.41 of the same kind of products.
Study of dynamic load identification under unknown initial conditions
Authors: Chen Shuang , Jiang Jinhui 
Published: May 2023

Abstract
Dynamic load identification belongs to the second inverse problem of structural dynamics, i.e. the inversion of the load history in the real state by collecting the measured data of structural vibration. Some traditional dynamic load identification methods do not consider the initial conditions, i.e. the initial conditions of the structure are assumed to be zero, however, the structure is not always at rest during the process of collecting the vibration response, which leads to a large error between the identified force and the actual force using traditional methods. Since the measurement of initial conditions is very difficult, in order to solve the influence brought by the initial conditions to the dynamic load identification process, this paper proposes a method based on sparse regularization to identify the load history under unknown initial conditions. Firstly, the unknown force is represented using basis functions, and the vibration response of the structure is divided into two parts: forced vibration caused by the force and free vibration under the initial conditions, and finally sparse regularization is used to solve the ill-conditioned equation. The experimental and simulation results also further verify the applicability and robustness of the method proposed in this paper in dealing with the load identification problem under unknown initial conditions.
Dynamic simulation of nozzle structure based on thermal-fluid-solid coupling analysis
Authors: Jia-hui Yuan , Ke Wang , Xiu-cong Gu 
Published: May 2023

Abstract
Many engineering structures are subjected to the combined action of thermal field, flow field and vibration load during use. The mechanical analysis of this kind of structure has important theoretical significance and engineering practical value. However, due to the complexity of multi-field coupling, it is difficult to analyze dynamic response and dynamic strength. A method to simplify the thermal-fluid-solid coupling model for specific engineering issues was proposed aiming at modeling the actual situation in which the high temperature field of the engine nozzle structure is relatively stable. Heated grid reconstruction, thermal modal analysis technology, and fluid-structure coupling response calculation method based on modal superposition were taken to obtain the load distribution and dynamic response level of the engine nozzle structure under the condition of thermal-fluid-solid coupling, which created conditions for structural dynamic strength evaluation including the prediction of vibration fatigue life. The test structure of an engine nozzle was taken as an example to perform dynamic response calculation and fatigue life prediction under thermal fluid-solid coupling conditions. Then the location of weak parts of the structure was identified, and effective suggestions for design improvement was put forward. Compared with the actual test results, the feasibility and accuracy of the method are preliminarily verified.
A use-case-driven approach for demonstrating the added value of digitalisation in wind energy
Authors: Barber S , Sempreviva A M , Sheng S , Farren D , Zappalá D 
Published: May 2023

Abstract
Digitalisation is one of the key drivers for reducing the costs and risks of wind energy. When considering whether to embark on a digitalisation initiative, two key questions arise. The first is what business or operational opportunities might feasibly be addressed and the second is which of the many potential aspects of digitalisation are relevant to those opportunities. In this work, we show how these questions can be answered with a use-case-driven approach, based around a survey aiming to collect and collate the main ”pain points” (or everyday challenges) of people in the wind energy sector. Although the relatively low number of participants of the survey (46) means that the results should only be used indicatively, it is still possible to make some general recommendations for priorities for digitalisation efforts in the wind energy sector. Firstly, digitalisation efforts should focus both on supporting people carrying out cross-lifecycle tasks, in particular sharing data, managing data, undertaking general data analyses and accessing data. Tools to do this should deal with varying data formats and naming conventions, make metadata more accessible, define data and metadata standards, make more data publicly available and improve the quality of data. Secondly, efforts should also focus on supporting people in the wind farm operational phase, in particular with failure detection, fault diagnosis, failure rate modelling and predictive maintenance. Solutions to do this should focus on accessible and validated tools for fault detection, cloud or other data pipeline solutions for SCADA data and tools for exhaustive data documentation. Finally, digitalisation efforts should focus on better communicating and helping people become aware of existing solutions and tools, as well as on helping people to exert a stronger influence on possible solutions.