bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disturbance rejection of interconnected positive systems
Authors: Guo Yu , Xu Shengyuan , Du Baozhu 
Published: February 2024

Abstract
This paper investigates the issue of stability of interconnected systems, where the systems are composed of perturbed positive subsystems and a interconnection matrix. To address the challenge posed by disturbances, a disturbance observer is formulated for disturbance estimation. The estimated disturbance is incorporated into the input of a controller, which is crafted to produce control inputs reliant on both the system state and the estimated disturbance. Using linear copositive functions, a controller design methodology based on linear programming is established. Ultimately, the efficacy of the proposed approach is substantiated through the illustration of numerical example.
Research on motor speed control based on the improved genetic algorithm to optimize fuzzy PID
Authors: Liu Weijun , Zhou Zhiyong , Cao Yinhai 
Published: February 2024

Abstract
This study aims to optimize the speed control effect of fuzzy PID controller in brushless DC motor control, and improve the traditional genetic optimization algorithm to improve fuzzy PID algorithm, mainly for genetic algorithm coding, crossover, and mutation process. In the three processes of the genetic algorithm, real number field coding is used, Taguchi orthogonal table is introduced into the cross-process, and Gaussian variation is applied to the mutation process. In the part of model construction and verification, this study uses Simulink software to build a brushless DC motor model and sets the same conventional parameters for simulation. The simulation results show that the algorithm overshoot and stability time of the fuzzy PID controller optimized by the improved genetic algorithm are obviously improved.
Departure Device Design With Dual Redundancy for the Assistant Landing Gear of Long-endurance UAV
Authors: Yang Tao , Wang Gang , Liang Dong 
Published: February 2024

Abstract
In modern wars and regional conflicts, in order to reduce casualties, more and more unmanned equipment and weapons are utilized. Among them, the UAV is the new favorite in the sky. Application fields of the military UAV are wide and varied. It is found to be used for intelligence reconnaissance, battlefield surveillance, as well as strikes. As for the scout UAV, long endurance is of utmost importance. There is no denying that less weight can result in longer endurance. A departure device for the assistant landing gear of a long-endurance UAV is designed in this paper. The system constitution and working principles are introduced in the beginning. Then, detailed system designs are presented, including the hardware design, software design, and other parts of the departure device. Several static and dynamic experiments are conducted to prove its feasibility. At last, the conclusion part summarizes its applications.
Research on Real-Time Calculation Method of Transformer Temperature Field Based on Reduced Order Model and Sparse Measurement
Authors: Wu Tao , Yang Fan , Farooq Umer , Liu Zhi , Jiang Jinyang 
Published: February 2024

Abstract
The lifespan of transformers is closely related to their operating temperature. Among the existing temperature acquisition methods, the measurement method cannot obtain the complete temperature field temperature, while the numerical calculation method presents the challenge of significant computational expenses. This study theoretically derived how to determine the real-time temperature distribution of transformer windings based on sparse measurement data and reduced order models and solved sensor layout issues, including the number and placement position of sensors. In this study, the maximum calculation error of the temperature distribution is 1.8 K, and the calculation time is 0.38 seconds. The research findings suggest that multiple modes can contribute to the temperature distribution of a transformer. Under a constant load condition, the calculation of transformer temperature can be achieved by utilizing a temperature sensor positioned at the hot spot in conjunction with the first mode.
Investigation on conduction heat dissipation for thermal management in distributed multi-point electronic chips
Authors: Zhan Dongdong , Zhou Jie , Qian Jiyu , Cao Yu 
Published: February 2024

Abstract
A conduction thermal dissipation system is designed for the thermal management of distributed multi-point electronic chips. The heat from the chips is conducted to the flow channel on the two sides with the help of heat pipes. For the purpose of improving the heat dissipation performance, the influence of different flow channel structures was analyzed with the help of numerical simulations. When the fin thickness and spacing are 0.4/0.5 mm, the heat transfer performance is optimal with acceptable flow pressure drop. The results indicated that temperature and uniformity meet the requirements of the electronic chips. The temperature of the chips is lower than 80°C at 1500 W under the condition of the 35°C ethylene glycol solution with 200 L/h. The impact of thermal interface materials on thermal performance was also experimentally studied. The results showed that the graphite interface material has an excellent comprehensive performance with good thermal conductivity and convenient application. This method of distributed multi-point chips and two-sided heat dissipation is more effective in fully utilizing the advantage of heat pipes compared to the traditional usage of evaporation and condensation located on the two sides.
Design of a teleoperated and mixed reality-based electric power live line working robot
Authors: Wang Yi , Qu Fengrui , Wang Xijun , Zeng Songtao , Sun Qizhen , Li Mengyang , Ge Jiafei 
Published: February 2024

Abstract
This paper presents a novel teleoperation force feedback approach combining graphic and haptic feedback for enhanced telepresence. Visual force feedback is modeled through a fitting process, with the force direction established through coordinate transformations. To construct operational environments, a new scene recognition and reconstruction technique is proposed, based on the principles of binocular stereovision. This method is primarily designed for live-line work scenarios, focusing on power line wires. It involves image preprocessing, target image recognition and extraction, binocular stereo measurements, generating depth point clouds, and ultimately reconstructing three-dimensional models of the target objects. Ultimately, a novel electric power live line working robot system with a strong sense of telepresence is achieved, based on teleoperation and mixed reality.
Research on a soft-start method for LCC-LCC compensated bidirectional wireless power transfer system
Authors: Wang Dongsheng , Lin Jinwei , Zhang Le , Ji Tao , Wang Tao 
Published: February 2024

Abstract
The increased popularity of electric vehicles and the pursuit of user convenience makes bidirectional wireless power transfer (BWPT) an attractive technology for charging batteries. To improve the transmission efficiency of BWPT and limit the external radiated magnetic field, it is necessary to ensure the zero-voltage switching (ZVS) operation of the converter on the transmitter-side and limit the transient start-up current of the inverter when the system is working. To solve this problem, this paper proposes a soft-start modulation strategy based on an H-bridge inverter on the transmitter-side. First, the circular characteristics of dual LCC compensation topology are analysed based on an equivalent circuit. Secondly, according to the characteristics of the input impedance angle and current of the transmitter-side, a soft-start control method combining frequency and phase shift control is proposed. Finally, the feasibility of the proposed soft-start modulation strategy is verified on a prototype.
Permanent magnet synchronous motor demagnetization fault diagnosis based on leakage radial magnetic density
Authors: Zhang Meng , Yu Yinquan 
Published: February 2024

Abstract
A method of demagnetization fault diagnosis of permanent magnet synchronous motors is proposed by measuring the radial magnetic density of the leakage field at the external space point of the motor. The method enables non-invasive diagnosis of motor permanent magnet demagnetization faults compared to other methods. In this paper, an analytical model of the radial magnetic density of the leakage field of a surface-mounted permanent magnet synchronous motor under no-load conditions is proposed, and its accuracy is verified by simulation. The influence mode of demagnetization fault on the radial magnetic density of the leakage field is analyzed, which provides a new idea for the diagnosis of motor demagnetization fault.
Transfer operation ride though control strategy of the aircraft power supply system with lithium battery energy storage
Authors: Zhang Xiao , Bu Yuheng , Tian Zhiyuan , Yao Wenli 
Published: February 2024

Abstract
The aircraft power supply system turns towards multi-source, and transfer operation will likely happen during flight missions and fault conditions. The transfer may lead to voltage interruptions and current surges, adversely affecting power quality. This paper proposes incorporating a lithium battery energy storage system (ESS) into the aircraft high-voltage direct current (HVDC) power system. The ESS employs a voltage control model with a lower voltage reference base, facilitating a smooth transfer operation during power interruptions. This approach reduces voltage fluctuations in the power supply system, enhances power quality, and enables seamless power transfer during the transfer operation.
Startup control strategies for pre-fabricated synchronous condensers using static frequency converters
Authors: Zhu Hongchao , Zhang Jie , Zhang Yin 
Published: February 2024

Abstract
In ultra-high voltage transmission systems, a considerable number of dynamic reactive power compensation devices must be equipped. Synchronous condensers are capable of providing substantial amounts of dynamic reactive power. Therefore, distributed prefabricated synchronous condensers can be deployed in ultra-high voltage transmission systems to supply reactive power support to the power grid. The start-up of synchronous condensers can only be achieved through external means. Currently, there are multiple start-up methods available for small-capacity prefabricated synchronous condensers. With the rapid advancements in frequency conversion technology and power electronics, static frequency converters (SFCs) can be utilized to initiate synchronous condensers. This paper investigates the principles of SFC start-up and coordinated control while also configuring protective devices for SFCs based on their structural characteristics and operational principles. A validation platform consisting of one SFC starting two synchronous condensers was established to analyze their start-up time, yielding results demonstrating the ability of SFC-driven distributed small-capacity synchronous condensers to rapidly adjust the power quality of the power grid.
An improved YOLOv5-based model for automatic PCB defect detection
Authors: Li Quanzhou , Zheng Qingwen , Jiang Shixin , Hu Ning , Liu Zhenguo 
Published: February 2024

Abstract
The detection of PCB defects plays an important role in PCB production. To meet the requested quality standard, systematic research was invested in PCB defect detection. The existing PCB defect detection methods are mainly trained by using an artificial defect image dataset, which is much more ideal than the real PCB production process. To deal with the real PCB production defect detection, we collected 3239 image samples and labeled each of them by label-image tool. This paper proposed a new model improved from the basic YOLOv5 framework, adding a scale and self-attention mechanism. The results revealed that this model performed well on defect location and classification with its mAP0.5 reaching 63.4%.
State/fault Estimation and Fault-tolerant Control by SOS approaches under Unmeasurable States
Authors: Liu Yixuan 
Published: February 2024

Abstract
This paper constructs a novel state/fault estimation (SFE) observer and integrated fault-tolerant controller for a series of tunnel diode circuits based on SOS approaches. The unmeasurable states are taken into consideration, expanding the application scope of the method, while a reduced-order observer is proposed to lighten the computational burden. The fault-tolerant control (FTC) unit is co-designed considering the estimation error, and a decoupling technique is employed to reduce computational complexity. For lower conservativeness, stable constraints ensuring the stability of the augmented system under H
∞ performance γ are given in the format of sum-of-squares (SOS). Finally, the validity of the proposed method is verified through a simulation experiment of a tunnel diode circuit.
Study of chromaticity correction methods for a hybrid multi-bend-achromat lattice
Authors: Liu Tao , Wang Lin , Luo Qing 
Published: February 2024

Abstract
The hybrid multi-bend-achromat (MBA) lattice is developed for the demand of higher luminosity at both collider and synchrotron light source. For a hybrid MBA lattice, its negative chromaticities must be corrected with sextupoles, which lead to nonlinearities, thus limiting the dynamic aperture (DA) and momentum aperture (MA). To get efficient injection and long beam lifetime, these nonlinearities must be carefully handled, while it is always difficult to optimize the nonlinearities with limited knobs for the fixed linear lattice. Therefore, conducting chromaticity correction is of importance in linear lattice design that can achieve better nonlinear dynamics. In this paper, three chromaticity correction methods are compared using multi-objective genetic algorithm (MOGA). A hybrid MBA of 2 GeV, as an example, is designed with a natural emittance of 4.4 nm•rad.
Temperature-dependent void nucleation and growth in single-crystal and nanocrystalline iron at extreme strain rates: atomistic insights
Authors: Wang Yuntian , Yang Min , Wei Qiujie , Zhang Ying 
Published: February 2024

Abstract
In this paper, we use molecular dynamics simulation with the embedded atomic method to perform triaxial deformation experiments on single-crystal and nanocrystalline iron at a strain rate of 5×10−9 s−1 and investigate the temperature effect on the void nucleation and growth process. We also evaluate the applicability of the Nucleation And Growth (NAG) model for single-crystal iron. The results indicate that the maximum tensile stress of both single-crystal and nanocrystalline iron decreases as temperature increases, with a reduction of 35.9% for single-crystal iron and 36.2% for nanocrystalline iron from 100 K to 1100 K. It is demonstrated that void nucleation and growth is more favored at high temperature. The void nucleation and growth process in single-crystal iron under high strain rate follows the NAG model. We analyze the sensitivity of the NAG parameters at different temperatures and find that the void nucleation and growth threshold of single-crystal iron is much higher than that of low carbon steel. The results can provide insights for developing fracture models of iron at extremely high strain rate and describing the dynamic damage at continuum length scales.
Design and performance analysis of a discontinuous spiral baffle heat exchanger
Authors: Pan Jin , Jin Feng 
Published: February 2024

Abstract
In this paper, a new type of heat exchanger with discontinuous spiral baffles is designed, and its performance on heat transfer is analyzed by numerical simulation. The research results show that the airflow in shell-side flows by a similar helical way, “Flow dead zone” is not found. The high enthalpy airflow’s temperature decreases about 38% of the inlet air temperature by cooling down with a convective heat transfer coefficient of 344.4 W/(m2·K), while the decrease of the airflow pressure is 30%.
Effect of cavitation on vortex-induced vibration of hydrofoil
Authors: Li Jiangtao , Hu Jian , Zhao Zhenxing , Duan Chuanzhi , Li Fugeng 
Published: February 2024

Abstract
Vortex induced vibration (VIV) is frequently observed in marine structures in offshore platforms, ships and other structures. Under specific circumstances, the vortex shedding frequency is locked into the natural frequency of the structure, resulting in significant and destructive vibration. Moreover, the cavitation in the wake vortex also cause strong trailing edge vibration. In this study, the interaction between VIV and cavitation of two-dimensional hydrofoil was adopted the Shear Stress Transport K-omega model and the Schnerr–Sauer cavitation model. The research findings indicate that the frequency of the wake vortex increases with the decrease of the cavitation number, but the vibration amplitude decreases.
Structure and impedance of TiN coated 304L SS substrates
Authors: Kotlarski G , Ivanov N , Dechev D , Valkov S , Mateev V , Marinova I 
Published: February 2024

Abstract
In the present work, the effect of the deposition time on the structure and electrical impedance of reactive DC magnetron sputtered TiN coatings was studied. The structure of the coatings and the substrates was studied using X-ray diffraction (XRD). The electrical impedance and high frequency stability of the specimens was experimentally measured and the results were indicative of whether the application of the coatings as protective layers between the electrical contact pads of electrical contact systems is feasible.
Rationally designed ultra-fast laser surface texturation of biocompatible temporal scaffolds
Authors: Angelova L , Daskalova A , Rabadjieva D , Sezanova K , Filipov E , Vila X M , Tomasch J , Hromada C 
Published: February 2024

Abstract
The aim of the current work is to create 2D silk fibroin and 3D calcium phosphate temporal cellular scaffolds with specifically enhanced porous topographical design by means of femtosecond laser-induced nano- and micro-scale hybrid surface structuring for application in muscle and bone tissue engineering. The created cellular matrices were ablated in a multistep manner using a Solstice Ace system, delivering laser pulses with pulse duration of 70 fs, at λ=800 nm and a focus spot of 25μm. The samples were positioned on a motorized XY translation stage perpendicular or in a variable angle in respect to the laser beam. Based on the previously performed comparative experimental study, optimal laser structuring conditions and raster patterns were chosen for further enhancement of muscular and Schwann cells environment. The most valuable contribution of the study presented is related to the optimization of the bioactivity properties of the studied cell matrices and their subsequent practical application in tissue engineering.
Ellipsometry of very thin Al2O3-HfO2 stacks for nano-memory applications
Authors: Karmakov Y , Spassov D , Paskaleva A 
Published: February 2024

Abstract
Nowadays, the way towards manufacturing of advanced flash memory devices with conformal layers in stacks or laminates depends on their physical characterisation, i.e. the layer and interface thicknesses, density and composition. The transition dimension between thin and very thin stacks is in the range of few nanometres. The assumption that the oxide layer properties in the very thin stacks are constant in depth or are the same as for the bulk material values is not correct. We have applied ellipsometry (Variable Angle Spectral Ellipsometry, and Multiple Angle Incident Ellipsometry) with appropriate algorithms for data interpretation to investigate very thin Al2O3/HfO2 stacks (5 bioxide blocks) grown by ALD with a total thickness below 20 nm. Depth profiling was used in simulations as a complimentary tool. A quantitative determination of HfO2 volume fraction in the stack depth was obtained. An independent determination of the thicknesses and the composition of blocks in the stacks were achieved. Lorenz-Lorentz mixing model was applied for the estimation of dielectric properties of the different layers in the stack depth.
Comparative study of the sidewall shape and proximity effect in bilayer electron beam resist systems
Authors: Nemec P , Vutova K , Bencurova A , Andok R , Kostic I 
Published: February 2024

Abstract
The experimental investigation and simulation of electron beam lithography (EBL) for bilayer and trilayer resist systems have been carried out. Important parameters of the EBL process, such as dissolution rate, resolution, absorbed energy, and resist profile in the investigated bilayer resist systems, have been studied and discussed. Various combinations of resist layers with positive electron resist have been proposed to examine the effects of lithographic process parameters on the resist profile. The results of this work are intended for use in multilayer resist systems to produce high-frequency electronics, where the fabrication of a T-shaped gate is one of the most crucial processes.
Electrochemical assessment of the barrier ability of galvanic Zn coating primers electrodeposited on low-carbon steel
Authors: Girginov Ch , Kozhukharov S , Boshkova N 
Published: February 2024

Abstract
Low-carbon steel is highly susceptible to corrosion, necessitating protective coatings capable of efficiently shielding its surface from corrosive environments. This brief research focuses on evaluating the protective capacity of electrochemically deposited Zn coatings, both with and without the addition of benzalacetone. Two independent electrochemical methods, Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Scanning (PDS), were employed after exposing the samples to a 0.01 M NaCl model corrosive medium (MCM) for 24 hours. The results demonstrate the discernible barrier performance of the Zn protective films compared to the bare steel substrates.
Growth of 2D MoS2 on sapphire and mica
Authors: Napoleonov B , Petrova D , Rafailov P , Videva V , Strijkova V , Karashanova D , Dimitrov D , Marinova V 
Published: February 2024

Abstract
In this work, we present a study on the epitaxial growth of MoS2 on both sapphire and mica substrates using the Chemical Vapor Deposition (CVD) method. The research focuses on optimizing the growth conditions in order to achieve reproducible results and explore the potential of conventional and Van der Waals epitaxy for synthesizing nanolayers and nanoclusters of transition metal dichalcogenides. By carefully selecting appropriately oriented substrates and performing targeted surface modification, we successfully achieved the desired epitaxial growth. The properties of the obtained structures are thoroughly investigated, with emphasis on their potential applications. This research contributes to the development of scalable and high-quality Transition Metal Dichalcogenide (TMD) growth technique, opening prospects for practical applications in various fields.