bluuebunny/crossref_metadata_2025 huggingface dataset:
Robust optimization of a radiotherapy pretreatment preparation workflow
Authors: Hoffmans-Holtzer Nienke , Smolenaers Luuk , Olofsen-van Acht Manouk , Hoogeman Mischa , Balvert Marleen , Petit Steven
Published: August 2023

Objective. Increasing cancer incidence, staff shortage and high burnout rate among radiation oncologists, medical physicists and radiation technicians are putting many departments under strain. Operations research (OR) tools could optimize radiotherapy processes, however, clinical implementation of OR-tools in radiotherapy is scarce since most investigated optimization methods lack robustness against patient-to-patient variation in duration of tasks. By combining OR-tools, a method was developed that optimized deployment of radiotherapy resources by generating robust pretreatment preparation schedules that balance the expected average patient preparation time (F
mean) with the risk of working overtime (RoO). The method was evaluated for various settings of an one-stop shop (OSS) outpatient clinic for palliative radiotherapy. Approach. The OSS at our institute sees, scans and treats 3–5 patients within one day. The OSS pretreatment preparation workflow consists of a fixed sequence of tasks, which was manually optimized for radiation oncologist and CT availability. To find more optimal sequences, with shorter F
mean and lower RoO, a genetic algorithm was developed which regards these sequences as DNA-strands. The genetic algorithm applied natural selection principles to produce new sequences. A decoder translated sequences to schedules to find the conflicting fitness parameters F
mean and RoO. For every generation, fitness of sequences was determined by the distance to the estimated Pareto front of F
mean and RoO. Experiments were run in various OSS-settings. Main results. According to our approach, the expected F
mean of the current clinical schedule could be reduced with 37%, without increasing RoO. Additional experiments provided insights in trade-offs between F
mean, RoO, working shift length, number of patients treated on a single day and staff composition. Significance. Our approach demonstrated that OR-tools could optimize radiotherapy resources by robust pretreatment workflow scheduling. The results strongly support further exploration of scheduling optimization for treatment preparation also outside a one-stop shop or radiotherapy setting.
Patient specific quality assurance in SBRT: a systematic review of measurement-based methods
Authors: Malatesta Tiziana , Scaggion Alessandro , Giglioli Francesca Romana , Belmonte Gina , Casale Michelina , Colleoni Paolo , Falco Maria Daniela , Giuliano Alessia , Linsalata Stefania , Marino Carmelo , Moretti Eugenia , Richetto Veronica , Sardo Anna , Russo Serenella , Mancosu Pietro
Published: August 2023

This topical review focuses on Patient-Specific Quality Assurance (PSQA) approaches to stereotactic body radiation therapy (SBRT). SBRT requires stricter accuracy than standard radiation therapy due to the high dose per fraction and the limited number of fractions. The review considered various PSQA methods reported in 36 articles between 01/2010 and 07/2022 for SBRT treatment. In particular comparison among devices and devices designed for SBRT, sensitivity and resolution, verification methodology, gamma analysis were specifically considered. The review identified a list of essential data needed to reproduce the results in other clinics, highlighted the partial miss of data reported in scientific papers, and formulated recommendations for successful implementation of a PSQA protocol.
A wireless physiological parameter monitoring system with a treatment feedback function during neonatal phototherapy
Authors: He Ziliang , Zhang Benjin , Zhang Jing , Xiao Zhenghua , He Ling , Yang Gang
Published: August 2023

Objective. Neonatal jaundice is a common condition in the early stages of newborns, and phototherapy is a fast, safe and effective method that is used to treat it. However, recent studies have shown that phototherapy may elicit side effects in infants, such as hypothermia, hyperthermia and dehydration. To improve the quality of phototherapy and the prognosis of patients, the changes in neonatal physiological parameters during phototherapy should be monitored to give better feedback to pediatricians or the phototherapy system. However, the current standard of clinical care during neonatal phototherapy with hard-wired devices limits this realization. Approach. Here, we developed a prototype of a neonatal wearable device, which can wirelessly potentially monitor the jaundice value, transepidermal water loss, skin wettedness factor and body orientation during phototherapy, and conducted prototype validation experiments. We also set up user-friendly interfaces and an analysis system on custom software, all designed to make the future addition of data interfaces for treatment feedback functions easier. Main results. The preliminary in vitro experiment demonstrated the effectiveness of simultaneous monitoring of the required physiological parameters. And further suggestions and specific operations are discussed in terms of optimization of the treatment of neonatal jaundice. Significance. It is believed that the established system has the potential to provide a basis for future phototherapy nursing guidelines and physiological monitoring standards.
Metamaterial-based acoustic enhanced sensing for gearbox weak fault feature diagnosis
Authors: Pan Huafei , Ding Xiaoxi , Qiao Hui , Huang Wenbin , Xiao Jiawei , Zhang Ying
Published: August 2023

In gear fault diagnosis of practical engineering, the gear fault signal is affected by external strong noise interference, the multipath superposition and interface loss of the internal fault excitation transmission, which leads to weak feature of incipient fault signals, making the gear fault diagnosis difficult. Inspired by the acoustic manipulation capabilities of acoustic metamaterials, this study proposes a method for weak gear fault feature diagnosis via gradient acoustic metamaterial (GAM), which utilises the acoustic rainbow capture and compression ability to reduce the difficulty of gear incipient fault diagnosis. According to the gear frequency modulation/amplitude modulation modulation principle, enhancement of fault feature frequencies can be achieved by collecting gear acoustic signals from the selected air gaps in GAM structure. In this study, the feasibility of GAM-based gear weak fault feature diagnosis is proved by experiments, which verify the multiscale feature denoising and frequency selective enhancement characteristics of GAM. The results show that the amplitude of the target signal is amplified more than eight times, the sideband component containing the fault signal is enhanced obviously, and the effect of denoising outside the target sideband is evident, making the fault feature can be easily identified from the weak fault signal after demodulation. By comparing with digital filtering in traditional signal processing, this method is more straightforward in extracting weak gear fault features. Additionally, this method adopts non-contact measurement method with micro-electroMechanical system (MEMS) microphone, which has advantages over acceleration sensors in overcoming the space limitation. All in all, the proposed method is effective and facilitates the identification of weak gear faults.
A self-loading suction cup driven by a resonant dielectric elastomer actuator
Authors: Wu Chuang , Cai Anjiang , Li Xiaozheng , Gao Xing , Cao Chongjing
Published: August 2023

Suction cups are widely utilized in industries and robotics fields for object manipulation and robotic positioning. Conventional vacuum pumps can remove fluid from the suction cup continuously, enabling reliable adhesion. However, the bulky and rigid nature limits their integration with soft robotics. On the other hand, suction cups driven by soft smart materials offer better integration with soft robots but face challenges in achieving continuous fluid removal, resulting in potential suction failures in case of seal breaks. Aiming to address this limitation, a novel self-loading suction cup driven by a resonant dielectric elastomer actuator is proposed. This mechanism allows for continuous and efficient removal of the enclosed fluid in the sucker, thereby achieving successful and sustained adhesion. The structure design is presented and its fundamental working principles are revealed through theoretical analysis and experiments. The effects of several key design parameters (i.e., actuation electric field amplitude, moving mass, substrate roughness) on the performance of the suction cup are experimentally characterized to achieve performance optimization. This design demonstrates a maximum net suction force of 24.9 N (12.7 kPa), which is equivalent to 80 times its body weight. The suction cup design holds potential application values in soft robots, surveillance and environmental monitoring.
A computational insight into Rb2ASbX6 (A=Tl, Cu & X=I, Cl) double perovskites for energy storage and optoelectronic applications
Authors: Qaid Saif M H , Jamil Muhammad , Munir Junaid , Ghaithan Hamid M , Ahmed Abdullah Ahmed Ali , Ain Qurat ul
Published: August 2023

Double perovskites are considered to be outstanding materials for encountering the energy crises faced by the world community. This article comprehensively addresses the electronic structure, mechanical, optical and transport attributes of Rb2ASbX6 (A=Tl, Cu & X=I, Cl) double perovskites by using the DFT approach. The structural and thermodynamic stability is confirmed with negative formation energy and tolerance factor. An indirect bandgap of 1.06 eV for Rb2CuSbCl6 and a direct bandgap of 1.12 eV for Rb2TlSbI6 have been found. Mechanical properties are analyzed through elastic parameters. The absorption is found in visible as well as in ultraviolet regions with the minimum energy loss suggesting their possible use in optoelectronic applications. The thermoelectric ability is judged through the computation of transport parameters. The ZT values of 0.79 for

Rb

2

CuSbCl

6

and 0.75 for

Rb

2

TlSbI

6

endorsed their potential for renewable devices.
Nonlinear electromagnetic force analysis and compensation control of electromagnetic linear actuator
Authors: Yu Peng , Tan Cao , Yan Hao , Ge Wenqing , Sun Zhaoyue , Chen Xuewei
Published: August 2023

Nonlinear electromagnetic force is a common phenomenon in electromagnetic linear actuators (EMLA). This nonlinearity limits the application in high-precision control systems. For facilitating the controller design, the influencing factors of nonlinear electromagnetic force were analyzed, and the quadratic polynomial with unknown weights was designed to approximate the nonlinear relationship among electromagnetic force, excitation current and displacement. An adaptive integral robust control algorithm based on electromagnetic force compensation (AIRC-FC) was designed, which combined the adaptive control law of electromagnetic force nonlinear compensation, stable feedback and error signal continuous integral robust control. The tracking performance and the adaptability of the EMLA with and without compensation control were analyzed under different loads. The results show that AIRC-FC improve the tracking performance of the EMLA effectively, and maintain high control accuracy under different loads.
PBHs and GWs from 𝕋2-inflation and NANOGrav 15-year data
Authors: Mansoori Seyed Ali Hosseini , Felegary Fereshteh , Talebian Alireza , Sami Mohammad
Published: August 2023

In this paper, we propose a novel mechanism in 𝕋2-inflation to enhance the power spectrum large enough to seed primordial black holes (PBHs) formation. To accomplish this, we consider the coupling function between the inflaton field and 𝕋2 = TμνTμν
term. PBHs formed within this scenario can contribute partially or entirely to dark matter (DM) abundance. Furthermore, the amplification in the scalar power spectrum will concurrently produce significant scalar-induced gravitational waves (SIGWs) as a second-order effect. In addition, the energy spectrum associated with SIGWs can be compatible with the recent NANOGrav 15-year stochastic gravitational wave detection and fall into the sensitivity range of other forthcoming GW observatories.
Sea Cucumber Identification Fishing System Based on Hog Super Pixel Feature Extraction
Authors: Wang Min , Liu Xin , Chen Zhenrui , Lorenzini Enzo
Published: August 2023

Due to the refraction, reflection and absorption of light induced by seawater and suspended particles, the image recognition of underwater vehicle has the problem of low accuracy and difficult localization, and to solve this one problem, an improved LSTM classification algorithm (CH-LSTM) based on CLAHE and HOG is given. First, the improved CLAHE algorithm is used to enhance image by image noise removal and de-fogging, the problems of underwater image distortion, fine lines, and abrupt changes are solved in the aquaculture waters image. Then, the Histogram of Orientation Gradient (HOG) operator is used for feature extraction to describe the shape of sea cucumbers and generate feature vectors; finally, the LSTM algorithm is used to classify the feature vectors and avoid overfitting through memory gates, so the generalization ability of the model was enhanced. The identification and sorting experiments of underwater fishing sea cucumbers show that the proposed algorithm is superior, especially in the environment of poor water quality, and the identification and localization accuracy of sea cucumbers is improved compared with the traditional ground SVM and BP neural network algorithms, and the identification accuracy is above 95.28%.
Construction Site Safety Helmet Wearing Detection Method based on Improved YOLOv5
Authors: Fu Liang
Published: August 2023

Aiming at real-time monitoring of whether the construction site workers wear helmets correctly according to regulations, we present an improved model which based on the fifth You Only Look Once (YOLOv5) target detection algorithm for helmet wearing detection. Firstly, the clustering algorithm of the network model in the YOLOv5 is optimized to design size of the bounding box. Second, by inducing multi-scale image input to adapt to different image sizes, which enhance the generalization ability of the model. Finally, Complete Intersection over Union (CIoU) instead of original Generalized Intersection over Union (GIoU). CIoU_Loss can entirely consider the distance which are from center point to the length-width ratio between prediction box and ground truth box. The result of final experiment demonstrate that the improved model has a strong identification capability. The detection average precision reach by 92.1%, which can meet can meet the precision demands in actual situations.
A Multi-hop Path Query Answering Model for Knowledge Graph based on Neighborhood Aggregation and Transformer
Authors: Zou Jun , Wan Jing , Zhang Hao , Zhang Yunbing
Published: August 2023

Multi-hop path query answering is a complex task in which a path needs to be inferred from a knowledge graph that contains a head entity and multi-hop relations. The objective is to identify the corresponding tail entity accurately. The representation of the path is a critical factor in this task. However, existing methods do not adequately consider the context information of the entities and relations in the path. To address this issue, this paper proposes a novel multi-hop path query answering model that utilizes an enhanced reasoning path feature representation to incorporate intermediate entity information and improve the accuracy of path query answering. The proposed model utilizes the neighborhood to aggregate the entity representation in the reasoning path. It employs a recurrent skipping network to splice the embedding of the relationship and the entity in the reasoning path based on their weight. Additionally, the model adds the position representation to obtain the reasoning path representation. Moreover, the model uses Bi-GRU and Transformer to obtain the local and global context features of each entity in the reasoning path. Finally, the reasoning path feature representation is input into the feedforward neural network and predicted through the softmax layer. The effectiveness of the proposed model in addressing the multi-hop path query answering task is demonstrated by experimental results on the WN18RR and FB15K-237 datasets. Specifically, the proposed model outperforms existing methods in terms of accuracy.
Research on the Solution of Electromagnetic Loop Network
Authors: Gao Wenman , Chen Xiang
Published: August 2023

This paper mainly studies the solution of the electromagnetic ring network. Firstly, the current situation and main problems of the electromagnetic ring network are analyzed, then the principles and ideas of the electromagnetic ring network are studied, and then the effect of the electromagnetic ring network is analyzed through example verification. Through the above research, it is concluded that the development and construction of the power grid should be accelerated in combination with the load and power supply planning to create conditions for decoupling the electromagnetic loop network and eliminate the adverse effects of the operation of the electromagnetic loop network.
Optimal scheduling method of air source heat pump heating station considering optimal power flow of distribution network
Authors: Liu Yongming , Xu Xiaokang , Song Zilong
Published: August 2023

Participation of adjustable loads in demand response can alleviate power supply and demand challenges. As a typical adjustable load, this paper gives an optimal scheduling method considering optimal power flow in distribution networks of air source heat pumps, and studies adjustable load power allocation schemes for multiple distribution network nodes. The scheme with the goal of the lowest network loss determines the scheduling amount of the corresponding node heat supply stations to achieve optimal power flow dispatch, and the genetic algorithm is used to solve the model. Specific examples analysis shows that the proposed decision-making method can reasonably allocate power adjustments, prevent node voltage overruns in distribution networks, and reduce active power losses.
Multi-axis Current Loop Control Based on FPGA
Authors: Hu Yaorong , Chen Yuran , Zhao Jian , Wu Shan , Zou Jiang
Published: August 2023

In this paper, according to the three-loop control structure, FPGA is used as the control chip of the current loop, and the parallel control of the multi-axis motor is realized by hardware nation. The current loop code is written in Verilog HDL language, and the simulation results of each control module are given by the SignalTap simulation tool. The main contents include a parallel sampling of the multichannel encoder, parallel sampling of multichannel current, vector coordinate transformation control (CLARK module, PARK module, IPARK module), PI controller module, etc. The results show that the rich logic resources and powerful parallel processing ability of FPGA enable a single FPGA to control multiple motors at the same time. Compared with the traditional serial execution of the program, this method greatly reduces the whole calculation time of the servo system.
Operational failure mechanisms of electromagnetic potential transformer
Authors: Qi Peng , Wu Weili
Published: August 2023

In response to the problem of transformers blowing up or even burning up together with detuning devices in recent years, an assessment method based on the equivalent of transformer winding currents is proposed for potential transformers (Potential Transformer, PT) in low and medium voltage distribution networks. Firstly, the damage mechanism of potential transformers is analyzed and the thermal breakdown is identified as the main cause of damage to the winding insulation. At the same time, the winding currents under different faults are analyzed theoretically to identify the characteristics of various fault currents. Secondly, an operational failure indicator based on thermal equivalence, i.e. the fault current threshold indicator, is proposed in conjunction with the general voltage transformer specification. Finally, the proposed indicator is verified by means of ATP simulation software and combined with simulation tests. The results show that the proposed index can accurately reflect the winding failure of potential transformers, and the research results can provide a reference for the selection of potential transformers and the prevention of insulation breakdown.
Partial Discharge Suppression of the Oil-impregnated Paper by Depositing PTFE Thin Film via Magnetron Sputtering
Authors: Li Yanqing , Hao Jian , Liao Ruijin
Published: August 2023

The rapid development of HVDC (High Voltage Direct Current) transmission technology brings new challenges to insulation materials. Oil-paper insulation needs to be strengthened to prevent possible breakdown failure. In this paper, the PTFE functional film was fabricated by magnetron sputtering on the insulation pressboard surface to suppress partial discharge. The partial discharge test was conducted to compare the withstanding ability of the modified pressboard and the untreated pressboard. The results showed that partial discharge inception voltage increased by 18% for the modified pressboard. Phase-resolved partial discharge results also showed a great enhancement in partial discharge withstanding the ability of the PTFE function layer on the pressboard. The molecular simulation was conducted to give a possible explanation for the improvement. Higher bond levels and a large band gap of PTFE played a vital role.
Characteristic Analysis of the Equivalent Experimental System for Electrodynamic Suspension Linear Generator
Authors: Yu Jiaqi , Wang Chengen , Wang Haoyun , Tian Jihao
Published: August 2023

This paper presents an equivalent experimental method for the linear generator of the electrodynamic suspension (EDS) system. Compared with the full-size experimental device, the proposed method can reduce the cost and difficulty of the experiment. Firstly, the working principle of the linear generator is described, and the numerical analytical expression for the induced voltage of the linear generator is derived. Based on the expression, the mapping relationship between the suspension coil current, system scaling ratio, and the induced voltage is clarified. Then, an equivalent experimental device was designed and built. Comparisons between the numeric analytical calculation, the finite element analysis, and the experiment have verified the accuracy of the equivalent experimental method.
A New Power-Frequency Oscillation Suppression and Power Allocation Control Method Based on MPC in Multi-VSGs Parallel System
Authors: Zhao Xuejian , Liu Jianzheng
Published: August 2023

The virtual synchronous generator (VSG) technology can provide frequency support for power systems that are dominated by renewable power sources. However, it also introduces the characteristic of active power oscillation, which can cause power-frequency oscillation between parallel VSGs when there are disturbances in the load power or command power. To address this problem, this paper proposes that the idea of equivalent comparison can be used to compare the power-frequency interaction of N-VSGs parallel systems with the current-voltage interaction of N-RLC circuits. This allows us to establish a mathematical model of the parallel VSGs system based on Kirchhoff’s equation of the circuit. Using this model, we designed a new power-frequency oscillation suppression and a power allocation control method based on the model predictive control (MPC) in multi-VSGs parallel systems. This method can effectively suppress power-frequency oscillation in each VSG branch after a disturbance occurs, and accurately allocate active power according to instructions. Finally, simulation results confirm the effectiveness of the controller.
Optimization of Wind Farm Design Layout based on the Non-Uniform Spacing Algorithm between Wind Turbines
Authors: Peng Huaiwu , Han Yi , Li Qian , Li Huaxiang , Zhang Rikui
Published: August 2023

The optimization of wind turbine layout is an important step during the design phase of wind farms, which directly influences the overall power performance and the profitability of the wind plants. The spacing distance between the wind turbines, which is often inconsistent in the prevailing wind direction and other directions, is the critical factor of wind turbine array layout optimization. With the considerations of the wind turbines’ safety in operation and the maximum utilization of wind energy resources comprehensively, an elliptic-constrained wind turbine layout optimization model is proposed in this paper. The stochastic optimal algorithm including the constraint checking and random searching processes is established to conduct the iterative calculation. It is proved that the annual energy production of the elliptic-constrained model with non-uniform spacing has increased in comparison with the conventional method. The proposed approach provides an effective engineering solution for improving the space utilization and the power output estimation of the wind farm.
The Coordinated Protection of the Whole Ship’s Power System of 143-meter Fishery Refrigerated Transport Ship
Authors: Nie Qin , Fang Jun , Shao Meibin , Lu Jinlong , Bao Dongdong
Published: August 2023

The selective protection of over-current is the focus of the protection of the entire ship’s power system, it ensures the reliability of safe operation of the ship’s power system. The article takes the 143-meter fishery refrigerated transport ship (No.992 Fuyuan Yuyun) as an example to analyze the selective protection of over-current, and the coordination analysis of various protective appliances is carried out.
Optimal Scheme of Remote Backup Automatic Switch Applied to Renewable Energy Grids
Authors: Yan Yabing , Huang Yong , Xu Liqiang , Ao Fei , Li Hui , Yang Jinyi
Published: August 2023

The support of renewable energy to the bus voltage during the grid fault period will cause the failure action of the backup automatic switch (BPAS). Moreover, the improper coordination of renewable energy and source supply lines in the process of BPAS operation will lead to the asynchronous close of a circuit breaker, which seriously threatens the stable operation of the power system. To solve the above problems, an optimal operation strategy applied to the remote BPAS is proposed in this paper. Firstly, the operation logic and characteristics of internal BPAS and remote BPAS are analyzed. Secondly, the mechanism of failure action and asynchronous close of a circuit breaker in regional power grids with renewable energy sources are analyzed. Then, to improve the speed and reliability of the BPAS, a strategy of remote BPAS operation suitable is proposed. To avoid the problem of failure action, by monitoring the low-frequency condition of the regional power grid, the strategy accelerates the bus voltage loss to shorten the operation time of the BPAS. Moreover, the operation conditions of BPAS are optimized to avoid the asynchronous close of the circuit breaker between renewable energy and source supply lines. Finally, the experimental results in the 110 kV transformer substation verify that the improved remote BPAS strategy can effectively improve the reliability and quickness of the grid connecting to renewable energy.
Control Strategy of Suppressing Short-circuit Current VSCs Feeding into the AC Grid in a Hybrid Cascaded UHVDC System
Authors: Li Tan , Zhao Zheng , Xiao Kun , Ma Weimin , Li Ming , Lu Yajun , Xu Ying , Zheng Kuan
Published: August 2023

Hybrid cascaded ultra-high voltage dc is a new dc technique with a line commutated converter cascaded with one or several voltage source converters. It is an effective solution for large capability transmission as well as improving the stability of the ac grid with multiple dc transmission systems feeding in. Baihetan-jiangsu dc project in China is the first cascaded ultra-high voltage dc project in the world. For a receiving end with a strong ac system, the short circuit current is always large and close to the maximum ac breaker breaking capability, which is a threat to the ac system fault clearance. In this paper, the issue of excessive short circuit current in a hybrid cascaded ultra-high voltage dc system is discussed and revealed. The process of the short circuit current developing is divided into 2 stages. Characteristics and the calculation method of the short circuit are proposed, and based on this, a control method is proposed, which can suppress the short circuit current during the fault clearance effectively. The parameter setting method is proposed. Finally, based on the scenario of the Baihetan-jiangsu dc project, the strategy and the parameters setting method are validated under PSCAD/EMTDC.
Inertia Evaluation of Wind Farm Under Overspeed Power Shedding Control
Authors: Wang Jin , Yan Jie , Liu Yongqian , Xu Zhicheng
Published: August 2023

As the penetration rate of wind power generation gradually increases in most grids, it is necessary to evaluate wind farms’ inertia to provide inertia information for electric grids and boost grid stability. This paper firstly models the inertia control mode of overspeed power shedding, which can realize the inertia control under the operation of different blade tip speed ratios, so that the wind turbine has a high inertia support capability. Then the energy change process in the inertia control process is analyzed, and the virtual inertia time constant is derived to evaluate a single unit’s inertia. Finally, a simple wind condition and the wind farm’s inertia control requirements in a day are simulated using an equivalent model, and the inertia level of the wind farm is calculated. The proposed research approach can alleviate the sophistication of inertia evaluation which also effectively consider the influence of inertia control.
Analysis and Suppression of Common Mode Interference in Flyback Switching Power Supplies
Authors: He Xinyu , Chen Yanming , Kong Fannie , Li Guojin
Published: August 2023

In the flyback power supply, with the increase of switching frequency, the electromagnetic interference caused by the power switch becomes more and more serious. In order to control the interference problem, the common mode (CM) interference noise source and transmission path of the flyback power supply are analyzed, the equivalent model of the transmission path is established, and the parameters affecting the common mode noise magnitude are deduced. On this basis, an active gate driver (AGD) circuit is proposed to suppress the noise generated by interference sources. The AGD circuit reduces the du/dt of the power switching tube by reducing the driving current during the turn-off dynamic period and thus achieves the reduction of the common-mode noise. Compared with traditional drive mode, the AGD can increase switching losses less at the same target. Finally, the feasibility of the AGD method is verified by experiments on the test platform.
Optimal Scheduling Method for the Integrated Energy System of the Park Based on Energy Consumption Differences
Authors: An Juan , Wang Xiaochen , Zhang Xiangcheng , Li Hongxia , Huang Cunqiang
Published: August 2023

Given the operation economy and reliability of the integrated energy system in the park, this paper first analyzes the differences in energy consumption. And then an optimal scheduling method for the integrated energy system of the park based on energy consumption differences is proposed, and the energy supply system of the park is economically scheduled, which can enhance the new energy consumption capacity, energy supply flexibility, and reliability of the system while ensuring the operation economy of the park. Finally, this paper selects an energy system for case analysis and suggestions. It is suggested that optimization operation strategies should be formulated from the perspective of the whole system of cooling, heating, and electricity supply, providing park-level precise energy supply services that are more in line with user needs, and improving the demand-side response market mechanism.
A standby mode for space advanced technology demonstration satellite
Authors: Li Jinsong , Yang Yingquan , Zhang Yonghe , Zhou Heng , Zhang Xiaofeng , Chen Wen , Li Dong , Liu Shuang
Published: August 2023

Standby mode is the mode in which the space advanced technology demonstration satellite (SATech) stays for a long time when all the payloads are not working. This mode ensures the energy supply of the satellite on the one hand and the long-term effectiveness of the satellite’s star tracker quaternion on the other hand. Firstly, the target guidance law in standby mode is designed. Secondly, the installation position of the star tracker is designed according to the characteristics of the guidance law. Thirdly, the rationality of the scheme is verified by simulation. Finally, the scheme has been verified to ensure the continuous efficiency of the quaternion of the star trackers and the satellite energy supply.
Experimental study on spray characteristics of RP-3 kerosene under the near critical condition with different injection conditions
Authors: Shi Pengyu , Fan Wei , Wang Zhisheng , Yu Qianqian , Liu Penghui , Ren Lishi
Published: August 2023

In an aero-engine, the effect of oil-gas mixing directly affects the working condition of the combustion chamber, and the mixing process of RP-3 kerosene near the near-critical point is more complicated because its physical properties are more strongly affected by its own temperature and pressure changes. The injection process of RP-3 kerosene near the near-critical point was photographed under different injection conditions using high-speed ripple shadowing technology. It was found that the increase in air injection pressure and the distance from the nozzle outlet to the cyclone outlet would reduce the jet expansion angle and jet width. The former would reduce the jet’s self-excited oscillation frequency, and the latter would increase it.
Crack nucleation mechanism of Ti60 titanium alloy under ultrasonic fatigue loading at different temperatures
Authors: Chen Chao-Lin , Shang De-Guang , Li Dao-Hang , Tang Zhi-Qiang , Han Zhao-Yun , Guo Yi-Er
Published: August 2023

The crack nucleation mechanism of Ti60 titanium alloy under ultrasonic fatigue loading at different temperatures was investigated. The results show that there are two different crack nucleation mechanisms at RT, 300 °C, and 400 °C, i.e., the oversized facet and oxide shedding crack nucleation mechanisms. Almost all fatigue cracks initiate in the form of oversized facets at RT. At 300 °C, the crack initiates at the oversized facet under the low load test, while the crack initiates at the oxide shedding site under the high load test. At 400 °C, all the fatigue cracks initiate at the place where the oxide shedding. Higher temperature and applied stress will help the oxide shedding crack nucleation mechanism to become dominant.
Design of PROFINET I/O Real-time Communication System between PLC Based on S7-1200
Authors: Chen Yun-Hai , Zhang Dong-Ying , Ji Jun , Chen Xin
Published: August 2023

Real-time communication means that the system processes external events within a defined time. The system configures a PROFINET I/O system between S7-1200 PLCs. By configuring the I/O controller and I/O equipment, setting the transmission area, and establishing the variable table and monitoring table, the system realizes the data exchange between the controller I/O and I/O equipment by observing the data transmission changes in the monitoring table.
Sky survey mission planning based on particle swarm optimization
Authors: Wang Yifan , Wang Hongfei
Published: August 2023

In 2024, China plans to launch the Chinese Space Station Telescope, and how to plan the telescope’s observing mission efficiently is of great importance. The space telescope mission planning faces many problems, like large observation areas, plenty of constraints, and difficulty in task optimization arrangement. In order to solve these problems, we consider the actual situation of the mission, take the telescope in-orbit constraint and observation constraint as constraints, and take energy consumption and observation efficiency as optimization objectives. We establish the sky survey mission planning model and sky survey planning algorithm based on multi-objective particle swarm optimization. The results show that the sky survey mission planning algorithm in this paper can effectively accomplish long-term sky survey mission planning and is more practical than existing algorithms.
The Effect of Suspended Sediment Concentration on Acoustic Propagation Based on Satellite Data Inversion
Authors: Zhang Yu , Tang Haichuan , Sun Hequan , Ren Wenhe
Published: August 2023

Suspended sediment in seawater not only affects the optical properties of seawater, such as transparency and color, but it also greatly affects the process of underwater acoustic propagation. The underwater acoustic detection equipment is affected by the change in suspended sediment concentration (SSC) in use. To address this problem, this paper deeply investigates the correlation between the characteristic parameters of acoustic propagation and SSC in different types of water bodies. It identifies the statistical characteristics of the temporal and spatial distributions of SSC in the Chinese seas through quantitative inversion based on satellite remote sensing data. It further analyzes the relationship between the concentration and distribution of suspended sediment and the characteristics of acoustic propagation of underwater weapons and equipment. Finally, it quantitatively evaluates the effect of SSC on the acoustic attenuation coefficient. This study can provide valuable references for the functional departments and base-level units of naval forces to make decisions and strategies for using underwater acoustic detection equipment.
Design and dynamics simulation of axial radial double locking satellite docking mechanism
Authors: Bai Bingtao , Xia Lurui , Li Sen
Published: August 2023

Aiming at the docking requirements of small satellites in orbit service, an axial, radial double-locking satellite docking mechanism was designed to realize the docking and separation of small satellites. Capture docking using the butt bar and the groove. The mechanism possesses multiple advantages, such as simple structure and fast response. A dynamic model considering contact, collision, buffering, and friction was established, and ADAMS software simulated the docking process. Apart from that, the dynamics and motion data of the mechanism were obtained. As revealed by the results, under the initial conditions of the general light and small docking mechanism, the mechanism can achieve the set task and complete the docking with a small collision force. What’s more, the buffer device can absorb 85.5% of the energy of the satellite, and the mechanism has a certain attitude correction ability. Altogether, this exploration can provide a reference for designing satellite docking mechanisms and formulating a docking strategy in the future.
Explosible Oxygen Concentration and Lower Explosion Limit of RP-3 Aviation Kerosene Vapor/O2/N2 Mixtures at Elevated Pressure and High temperature
Authors: Jin Zhao , Liu Jing , Ma Yichao
Published: August 2023

RP-3 aviation kerosene is widely used in China, and the critical explosible oxygen concentration (COC) and lower explosion limit (LEL) are important parameters concerned about aviation safety. The COC and LEL characteristics of RP-3 aviation kerosene vapor/O2/N2 mixtures at different initial temperatures and pressure were investigated experimentally. The LEL for RP-3 vapor/O2/N2 mixtures ranges from 0.5 vol% to 0.6 vol%, with the ambient pressure ranging from 40 kPa to 100 kPa, temperature from 60°C to 150°C, which is almost unchanged. The COC decreases as the temperature and pressure increase, and the COC of RP-3 vapor/O2/N2 mixtures is 9.7 vol% under the pressure of 100 kPa and 150°C. The suppression performance of N2 on the RP-3 vapor/O2/N2 mixtures was discussed, and the suppression performance model was defined in this paper, the suppression performance on COC condition is about 77%.
UAV Swarm Reconfiguration Based on Improved Artificial Physics and Virtual Structure
Authors: Zhao Hongchao , Zhao Jianzhong , Dong Xuexia
Published: August 2023

The reconfiguration problem was researched for the homogenous fixed-wing unmanned aerial vehicle (UAV) swarm. The kinematic model of a fixed-wing UAV was constructed. The virtual structure expressed the desired swarm configuration. A node in the virtual structure represented the desired position of a UAV. The improved artificial physics (AP) method used the node to produce the attraction to a UAV. The repulsion was designed for the UAVs to avoid collisions among them during the swarm reconfiguration. The UAV controller included the attraction, the repulsion, and the damp term. The damp term reduced the chattering process of the UAV’s flight states. A numerical simulation was carried out to show the reconfiguration process of the UAV swarm. The simulation results validate that the designed controller can drive the UAV to avoid collisions with other UAVs and to successfully complete the swarm reconfiguration process.
Ditching characteristics of civil aircraft with low-tail layout
Authors: Chen Shuyong , Luo Wenli , Chen Baoxing
Published: August 2023

Research focusing on the multi-phase coupling problem and ditching performance of a certain type of aircraft was carried out by the volume of fluid model and full-flow moving mesh method. Compared with the experimental results of the scaled model, the pressure predicted by this method matches well, and the maximum error of the pitch angle is less than 1.5°, which can accurately reflect the movement and load characteristics of the aircraft during ditching. On this basis, the influence of flat tails, flaps, and nacelles on the ditching performance is analyzed. The results show that it is not conducive to maintaining a stable attitude if the deflection of the flat tail is too slight, and the advance water-entry of flaps and nacelles will accelerate the decreasing process of pitch angle.
Performance Assessment of a Higher Bypass Ratio Engine Installation on a Rear-mounted Regional Aircraft
Authors: Chai Xiao , Liu Kaili , Zhong Yuan
Published: August 2023

The unceasing growth of the bypass ratio of civil aircraft engines reduces the specific fuel consumption while simultaneously complicating engine installation. This paper assesses the cumulative advantages of employing engines with superior bypass ratios in rear-mounted regional aircraft. The aerodynamic analysis of the engine intake and exhaust ramifications is based on the RANS CFD methodology, validated by the NASA CRM model and AIAA DSFRN model. An engine cycle model was developed to supply the engine inlet and outlet conditions for CFD calculations. In the case of the rear-mounted regional aircraft scrutinized herein, the fan diameter expanded from 53 inches to 60 inches, with the bypass ratio escalating from 5.3 to 11. This resulted in a roughly 9.33% reduction in specific fuel consumption. Nonetheless, the adverse impact of engine dimensions counteracts the cycle advantages, culminating in a 4.23% decrease in the aircraft’s lift-to-drag ratio and an aggregate benefit of 5.62%.
Experimental Study on Whipple Protective Structure under Low-Speed Impact
Authors: Dong Yucai , Sun Jing , Zhou Qin , Wang Jianjun , Gong Liming , Fang Jinyong
Published: August 2023

Aiming at the Whipple protective structure with a front plate of 3 mm 6061-T6 aluminum alloy and a rear plate of 3 mm 6061-T6 aluminum alloy, two different projectiles were used to conduct experimental research on the low-velocity impact Whipple protective structure. The relationship between the corresponding damage mode and the kinetic energy property of the projectile was analyzed. At the same time, the penetration velocity limit of the Whipple protective structure was explored to obtain the damage characteristics of this protective structure under cm-level low-velocity impact. The damage characteristics of the small projectile to the protection mechanism within the relative impact velocity of 650 m/s provide theoretical and technical support for the later spacecraft reinforcement optimization design.
Event-based Construction Method of Stratospheric Airship Test Scenario
Authors: Zhang Yongdong , Wang Ziwei , Huang Taiqin
Published: August 2023

Ground tests are needed to determine the system status before stratospheric airship flights. In order to realize the test under complex flight conditions, this paper proposes a method of constructing test scenes from test events. Firstly, the different operating conditions of a stratospheric airship during its flight are analyzed. On this basis, a test scenario covering key conditions is designed. Secondly, the test scenario is described in the way of events, and the composition of events under different test scenarios is given. Finally, the test scenes are generated by the condition simulation equipment, which is applied to the ground test of the stratospheric airship. The feasibility of this method is verified.
Study on Airfoils and Aerodynamics of High-Speed Aircraft Propeller
Authors: Zhang Kun , Yan Wenhui
Published: August 2023

To boost the aerodynamics of high-speed aircraft propellers, the lift-to-drag (L/D) ratio variation law and the Mach number contour distribution of flat-convex airfoil NACA4412, supercritical airfoil RAE2822 and thin airfoil at a high Reynolds number NACA65206 at different Mach numbers (Ma) and angles of attack (AoA) are investigated through computational fluid dynamics (CFD). After analyzing the lift and drag characteristics of the three airfoils, NACA65206 is selected to design a high-speed aircraft propeller. Then the flow field of the designed propeller is simulated through CFD, and its aerodynamic performance is calculated. The results show that NACA65206 exhibits a higher L/D ratio and gentler stall if the Mach number increases from 0.5 to 0.9. The designed propeller with NACA65206 is found to have propulsive efficiency exceeding 80% at Mach 0.6 in flight, and the value is over 75% when the Mach number in flight is 0.7. These values suggest that the high-speed aircraft propeller designed with a thin airfoil and a large back-swept angle exhibits satisfactory propulsive efficiency.
Structural development of the high-speed free jet test facility
Authors: Yu Zebin , Gao Xinyu , Cai Qingqing , Xie Qing
Published: August 2023

The 2 m×2 m high-speed free jet test facility is a 2 m level intermittent blowdown-ejector ground test facility, which has the ability of tri-sonic operation. The closed test section is replaced with a large test chamber. In the development process of the project, the main focus is the uncertainty influences of the jet pressure pulsation action on the facility, the functional realization of step change test Ma number by adjusting semi-flexible nozzle profile in a wide operating range for 2 m level facility, etc. These difficulties have been solved in various ways, such as theoretical analysis and calculation, adoption of multidisciplinary optimization techniques, a reasonable choice of vibration suppression means, and accumulation of rich experience in the field of wind tunnel design. At present, this facility has been built and debugged, and the integrity of the structure has been verified.
Airworthiness Requirements for Drainage Ground Test of Flammable Liquids from Transport Aircraft
Authors: Dong Jiaxuan
Published: August 2023

The leakage and ignition of flammable liquids such as fuel and hydraulic liquid on transport aircraft are extremely harmful to aircraft and passengers. The drainage design is an effective means to reduce the probability of ignition and the resultant hazards if ignition does occur. The drainage test is required to show compliance with Article 25.863, and the drainage ground test must be performed before the flight test. This paper deeply studies Draft AC 25.863 and gives the airworthiness requirements for the drainage ground test of flammable liquids in combination with model practice. It provides a reference for the ground drainage compliance verification in the flammable liquid leakage area of transport aircraft.