bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of phase separation on extinction times in population models
Authors: Schüttler Janik , Jack Robert L , Cates Michael E 
Published: August 2024

Abstract
We study the effect of phase-separating diffusive dynamics on the mean time to extinction (MTE) in several reaction-diffusion models with slow reactions. We consider a continuum theory similar to model AB, and a simple model where individual particles on two sites undergo on-site reactions and hopping between the sites. In the slow-reaction limit, we project the models’ dynamics onto suitable one-dimensional reaction coordinates, which allows the derivation of quasi-equilibrium effective free energies. For weak noise, this enables characterisation of the MTE. This time can be enhanced or suppressed by the addition of phase separation, compared with homogeneous reference cases. We discuss how Allee effects can be affected by phase separation, including situations where the tendency to phase-separate renders an otherwise stable population unstable.
Analysis of SIS epidemic model in bi-uniform hypernetworks
Authors: Wang Wenhui , Zhang Juping , Liu Maoxing , Jin Zhen 
Published: August 2024

Abstract
To describe the dynamics of epidemic spread with multiple individuals interacting with each other, we develop a susceptible-infected-susceptible (SIS) spread model with collective and individual contagion in general hypernetworks with higher-order interactions. The constructed model is applied to a bi-uniform hypernetwork to obtain a mean-field model for the SIS model. The threshold value at which an epidemic can spread in the bi-uniform hypernetwork is obtained and analyzed dynamically. By analysis, the model leads to bistability, in which a disease-free equilibrium and an endemic equilibrium coexist. Finally, numerical simulations of the developed model are carried out to give the effect of the proportion of individual contagion hyperedges on the spread of an epidemic.
CFD study on wake characteristics of a dual rotor wind turbine using different turbulence models
Authors: Yang Dinghua , Gu Xun , Li Changjie , Lin Fei , Jiang Zhiwei , Yang Minglong , Liu Zhenqing , Qi Zhihui , He Lanfei , Wu Songxiong 
Published: August 2024

Abstract
The computational fluid dynamics (CFD) method is widely used in wind turbine wake characteristics simulation. The dual-rotor wind turbine has attracted the attention of researchers because of the wind energy utilization rate that is difficult to surpass by the traditional single-rotor wind turbine. Using the CFD method to study the wake of the fan needs to complete the steps of modeling, meshing, simulation, and post-processing. Reynolds average Navier-Stokes (RANS) model and large eddy simulation (LES) model are two commonly used turbulence models in CFD calculation. The flow field can be simulated efficiently and accurately by using the considerate hybrid grid. This paper uses a full-scale wind turbine model, body-fitted hybrid grid, RANS, and LES turbulence models to conduct CFD numerical simulation on a dual-rotor wind turbine to analyze its wake characteristics. It was found that the LES model shows obvious advantages in instantaneous wind speed and vorticity, and the richness of its details is more helpful for researchers in analyzing the results accurately. The dual-rotor wind turbine shows the fusion of two wind turbine wakes in the far wake region, resulting in the expansion of the wake region and the irregularity of the far wake region.
The research on freezing performance in the cap-type stringers of composite fuselage
Authors: Song Mingliang , Li Lei , Zhou Zhao , Zhu Chuangfeng 
Published: August 2024

Abstract
Composite materials are increasingly used in civil aircraft, where there is water accumulation in the lower panel for special reasons, some of which can enter the interior of the cap-type stringers. The accumulated water inside the stringer undergoes a change of liquid-solid–liquid on each flight, and the thermal expansion and cold contraction caused by ice can have a stripping effect on the co-bonded interface of the stringer to the skin, which potentially causes delamination of the co-bonded interface of the stringer to skin and affects the flight safety. In this paper, the cap-type stringer structure of a common composite fuselage is used as an example to study the reciprocating change process of water in the stringer from liquid to solid. When the total number of cycles exceeds one time the flight life of 34000 cycles, there is some problem with whether the co-bonded interface of the stringer to skin exists the phenomenon of debonding. Due to physical freezing, melting, and the longer test cycle, establishing a similar finite element model is considered after completing appropriate physical tests. The physical change process is usually translated into the mechanical loading test to accelerate the test schedule. The test results showed that the loads from the thermal expansion and cold contraction caused by ice were very small, which caused no delamination of the stringer and the skin and had no effect on flight safety.
Experimental investigation on buffet load characteristics of a wide-body aircraft horizontal-tail in take-off configuration
Authors: Chen Zhenyu , Zhang Lingfeng , Liu Yang 
Published: August 2024

Abstract
Surface buffet load characteristics and structural response characteristics of the horizontal tail were measured and analyzed by installing a subminiature pulsating pressure sensor and root strain gauge on the horizontal tail surface of a rigid full model of a civil wide-body aircraft. The results show that, before buffeting onset, the vibration response of the horizontal tail structure is only affected by the incoming pulsating pressure, and the response frequency is near the natural frequency of the structure. The buffeting coefficient of the structure has a linear relationship with the incoming flow excitation. After buffeting onset, the buffeting load will propagate further along the chord direction of the horizontal tail, and the frequency range will also expand significantly, distributed in the wide frequency range of 20 Hz~1, 000 Hz and maintained at larger incidences.
Wireless passive condition monitoring system for aircraft
Authors: Luo Yuxiang , Cheng Xianfu , Zhang Qiang , Liu Tao , Yu Zhe , Zhu Qixing 
Published: August 2024

Abstract
In response to the risk of settling in the long-term storage of viscoelastic fuel in aircraft solid engines, this study proposes a fuel-settling monitoring system based on the cooperation of implanted optical fibers and wireless passive sensors for the first time. The system does not require wiring holes in the original structure of the engine, avoiding unpredictable damage to the structure. At the same time, the elastic modulus of the settlement monitoring sensor is similar to that of solid fuel, overcoming the problem of measurement uncertainty caused by the mismatch of elastic modulus in traditional sensors. The optical fiber grating sensor arrays are used to calibrate the wireless passive sensor array so that the wireless passive sensors have accurate strain monitoring ability. In the paper, the strain sensitivity coefficient of the wireless passive sensor is up to 230.4 Hz/με, which is important for accurate monitoring of settlement. The fuel settlement is obtained based on the deformation inversion model and more quantitative studies will follow. Finally, the long-term accurate monitoring of the fuel settlement in the confined space is realized.
Experimental study on cloud parameters in an open icing wind tunnel for aircraft ground icing tests
Authors: Zhou Qiongyao , Dong Mingsai 
Published: August 2024

Abstract
Supporting ground icing test of aircraft air intake system, this article uses a seasonal open icing wind tunnel to provide an artificial freezing fog environment. In order to verify that the freezing fog environment created by the seasonal open icing wind tunnel meets the test requirements, the impact of compressed air-water pressure ratio on MVD and the impact of water supply flow rate on LWC were studied in this article. Additionally, an ice thickness evaluation method based on an ice grid to test the uniformity of LWC within a range of 1 m×1 m was conducted. The research results show that: 1) When the compressed-water pressure ratio is 2.6±0.26 (M±SD), the MVD meets the test requirements; 2) LWC and water supply flow rate have a good linear relationship, and LWC increases linearly with the increase of water supply flow rate; 3) The uniformity of LWC within a range of 1 m×1 m can meet the requirements of ±20%, and the consistency between the two tests is good.
Measurement method of vacuum degree in satellite in vacuum thermal test of spacecraft based on diaphragm gauge
Authors: Wu Yue , Xue Cuiping , Xu Zhongxu , Wei Xi , Tao Dongxing 
Published: August 2024

Abstract
The vacuum degree near some instruments and equipment on the monitor is required in the vacuum thermal test of the spacecraft. Only when the vacuum degree meets the requirements, the equipment can be started up. This paper studies the new requirements of the thermal test of the spacecraft, analyzes the reasons why the conventional diaphragm gauge cannot work in a vacuum thermal environment, and designs a new diaphragm gauge. After testing and calibration, it is proved that it can be applied to the measurement of the vacuum degree in the satellite, so as to ensure that the instruments and equipment on the spacecraft can start up normally during the vacuum thermal test and accept the assessment. It effectively guarantees the smooth progress of the thermal test of the spacecraft.
Springback research of tubular structure under lateral compression using explicit and implicit FEA method
Authors: Zhang Ziqian , Zheng Chengyuan , Liu Jianzhi , Zhong Ying 
Published: August 2024

Abstract
The springback of laterally compressed thin-walled tubes is an important issue, which affects the prediction of tubular structure energy absorbing ability and the final sectional profile. So, the springback of laterally compressed tubes after plastic compression should be predicted and calculated in the process of the tube design. However, predicting the springback with traditional theoretical or experimental methods is hard. In the present paper, an explicit and implicit sequence-solving method based on ANSYS/LS-DYNA was developed for calculating and analyzing the springback of the tube under lateral compression by the code ANSYS LS-DYNA. The result implied that the explicit and implicit sequence-solving method is reasonable, and the values of the tube’s springback after lateral compression can be predicted by this FEA method.
Development of a small-sized mobile aerostat system
Authors: Wang Weixin , Wan Xiaogang 
Published: August 2024

Abstract
With the advantages of wide coverage, long endurance, rapid response, and high cost-effectiveness, tethered aerostats have become an attractive elevated platform to carry payloads to conduct surveillance and communication tasks in natural disaster rescue, crowd management, key assets protection, and border surveillance. The paper presents the development of a fast-response ellipsoidal aerostat system (FREAS) for surveillance and communication applications. Requirements for technical parameters, design and engineering, and field tests of the FREAS are described. The field tests show that video surveillance and relay communication performances fully meet expectations for the development. Future work to further verify and improve the aerostat system is finally addressed.
Composite waveform air supply method for air conditioning to improve aircraft cabin air quality
Authors: Cheng Haoyu , Lin Jiaquan , Gao Mei 
Published: August 2024

Abstract
To enhance the air quality in aircraft cabins during the waiting phase on the apron, a composite waveform signal aircraft cabin air supply which combined constant value signal with sinusoidal signal was proposed. In this study, a CFD technology was used to establish a Boeing 737 cabin model. Using NO2 as the bleed pollutant, the airflow characteristics within the cabin model were simulated when cabin air conditioning used constant value signal air supply, sinusoidal signal air supply, and composite waveform signal air supply. The evaluation of different air supplies was based on indicators such as the rate of mass fraction descent ROD, Draft Rating DR, and TAPPD. Additionally, a total efficiency coefficient function G(X) was constructed using the efficacy coefficient method. When the composite waveform signal was used for cabin air conditioning, the G(X) value was a 22.4% increase compared with using constant value signal air supply and a 5% increase compared with using sinusoidal signal air supply. These findings indicate that cabin air conditioning uses composite waveform signal air supply, and the air quality in the aircraft cabin is optimal.
A study on the method of obtaining field dynamic characteristic parameters of a rocket sled
Authors: Zheng Zhuowen , Shang Fei 
Published: August 2024

Abstract
In order to solve the problem of obtaining the accuracy of dynamic characteristic parameters in a rocket sled test, a multi-channel parallel storage test device for a rocket sled field test was designed and verified in the laboratory. With STM32 as the control core and NAND FLASH as the data memory, the multi-channel vibration, shock, and course acceleration signals can be collected, stored, and transmitted synchronously. Through laboratory verification, the performance test results of the system show that the system can complete the multi-channel 500 kHz sampling frequency parameter acquisition and storage, and can realize the normal acquisition of vibration, shock, and course acceleration signals under the environment of high-speed movement of a rocket sled.
Shock attenuation efficiency of different buffer materials during the separation of explosive bolts
Authors: Zhang Junjian , Gong Linhui , Gao Lijun , Liao Guoliang , Zeng Qinglei 
Published: August 2024

Abstract
Explosive bolts are widely used in spacecraft separation. Strong transient shock waves are usually generated during the unlocking process, which can influence the precision of the instruments inside the spacecraft. Therefore, reducing the shock generated during the explosive bolt-unlocking process is important in space engineering. This paper establishes a simplified numerical model for the explosive bolt separation process to investigate the shock attenuation efficiency of different buffer materials, including fluoroplastics, rubbers, and aluminum foams. The simulation results show that rubbers with a medium modulus can provide effective shock attenuation. For specific impact conditions, it is necessary to select aluminum foams with moderate platform stress to absorb the impact energy. If the platform stress is too low, it may result in an inadequate energy absorption capacity. In contrast, excessively high platform stress may limit plastic deformation, hindering the full utilization of energy absorption capabilities.
Design and experiment of a vertical fixed-wing UAV based on electric culver
Authors: Wu Wenqi , Ren Mengyuan , Long Yaosong 
Published: August 2024

Abstract
In recent years, drones have played an important role in warfare. In response to the issues of high noise, slow flight speed, and poor maneuverability of traditional rotary-wing vertical take-off and landing UAVs, as well as the complexities and high energy consumption of traditional tilt-rotor structures, a novel fixed-wing UAV with electrically controlled thrust vectoring based on the ducted fan concept was designed. Firstly, the selection and analysis of the wing landing gear were carried out. Secondly, the mechanism analysis and strength verification were conducted for the designed thrust vectoring three-axis rotating nozzle. Finally, a servo control method was proposed, and a prototype was manufactured for flight testing. The results validated that compared to similar power-level rotary-wing vertical take-off UAVs, the speed of this UAV increased by 43.2%, and the maneuvering radius improved by 56.79%.
Simulation of coaxial electrostatic atomization of nanofluids
Authors: Liu Jinyu , Su Yu , You Jiaxi 
Published: August 2024

Abstract
The microscopic characteristics of the coaxial electrostatic atomization of nanofluids have a very important impact on the field of cooling and lubrication. In this paper, a finite element model of coaxial electrostatic atomization of nanofluids is established by using the ternary phase field method in the voltage range of stable cone jets, and different outer and inner fluids are simulated to compare the influence of different inner and outer fluid types on the formation of cone jets and the broken droplets at the end of the coaxial electrostatic atomization of nanofluids. The results show that the formation of the coaxial conical jet is faster when the outer fluid is castor oil and its nanofluids. When the external fluid is sunflower oil and its nanofluids, the charge concentration volume force is higher than the outer fluid for castor oil and its nanofluids.
Simulation of the formation process of nanofluid electrostatic atomization under different voltages
Authors: Liu Pan , Su Yu , Liu Jinyu 
Published: August 2024

Abstract
Voltage has an impact on the electrostatic atomization effect of nanofluids. In this study, by using COMSOL software, a simulation model of electrostatic atomization of graphite water-based nanofluids under different voltages was established. The process of cone jet formation under different voltages was observed through three-dimensional visualization of volume fraction maps. The formation processes of graphite water-based nanofluid cone jets were analyzed from three aspects: electric field force, charge concentration, and volume force. The results indicate that the droplet formation speed increases with higher voltage. Under −10 kV, graphite water-based nanofluids exhibit faster cone jet formation, thorough breakup of droplets at the jet’s tip, and better atomization effects.
Research on the application of boiling heat transfer in microchannels of high power electronic chips
Authors: Wang Yalong , Zhang Yun , Zhou Dongliang , Liu Tao , Liu Fan , Tao Cheng , Yu Xingang , Miao Jianyin 
Published: August 2024

Abstract
For electronic devices with single chip heat consumption exceeding 600 W and heat flux density exceeding 50 W/cm2, the heat dissipation requirement of a single cabinet exceeding 50 kW provides a new solution for high heat consumption and high heat flux chip heat dissipation by combining boiling heat transfer with microchannels. The flow and heat transfer differences between microchannel and conventional channel evaporators were verified through experiments. The results show that compared with conventional channels, the heat dissipation temperature difference of microchannels is reduced by 44%. The slender structure of microchannel evaporators can achieve better heat transfer performance, and the flow boiling heat transfer coefficient can reach 2-3 W/cm2·K.
Study on passivation effect of dissolved hydrogen on primary material
Authors: Ai B , Liu C S , Lin G X , Sun Y , Tian Z H 
Published: August 2024

Abstract
In this project, 304L stainless steel, the key material of the boron-free primary circuit system, was selected as the research object, and three passivation process conditions were simulated by high temperature and high pressure circulation loop to study the influence of hydrogenation on the thermal passivation effect. Scanning electron microscope, transmission electron microscope and corrosion weight test were used to study the influence of dissolved hydrogen on the morphology, composition, film thickness and corrosion rate of the oxide film of the primary circuit material. The results show that: (1) the 304L stainless steel has a double-layer oxide film pore structure under the three passivation process conditions, and the corrosion rate is at a low level, and the corrosion rate decreases to a certain extent under the hydrogenation condition; (2) After hydrogenation, the thickness of the oxide film formed on the surface of 304L stainless steel becomes thinner and the surface oxygen content decreases, which may be related to the reducibility formed by hydrogenation.
Molecular Simulation Study on Corrosion Inhibition Mechanism of Ce Modified Carbon Point Corrosion Inhibitor for Carbon Steel
Authors: Li Fengting , Zhou Yi , Qu Wentao , Wang Zhikun , Hu Songqing 
Published: August 2024

Abstract
The molecular activity of Ce-doped carbon dots and their adsorption behavior on metal surface were studied by quantitative and kinetic calculation methods. It is found that Ce doping will become the reactive center of molecules, and the carbon point reaction activity is stronger after Ce atom doping. Carbon dots doped with Ce are more likely to be adsorbed on the surface of Fe. Due to the doping of Ce atoms, the nucleophilic and electrophilic activities of carbon sites have been enhanced, so the overall activity of molecules has been improved. The carbon point doped with Ce can more easily agree with the displacement of water molecules, thus achieving better protection effect. The performance of CeCD doped with monoatomic form will be slightly better than that of CeCDTC doped with CeO cluster form.
Evaluation of casing corrosion in different well sections and application of anti-corrosion schemes for shale gas wells in the southern Sichuan basin
Authors: Xu K W , Wang Y , Zhou L , Duan Y 
Published: August 2024

Abstract
The frequent occurrence of wellbore corrosion in shale gas development blocks within the southern Sichuan basin has led not only to the failure of well integrity but also severely restricted the safe and efficient development of shale gas resources. To address the challenge of well integrity failure caused by corrosion in shale gas wells, indoor experiments were conducted. These experiments were based on the typical service conditions of shale gas wells in two major blocks, C and L, located in the southern Sichuan basin. The aim was to evaluate the corrosion status of the entire well casing and analyze the underlying corrosion mechanisms. On this basis, a comparison was made including the corrosion resistance performance and the 20-year service feasibility of various anti-corrosion technologies. Based on the results, a casing anti-corrosion scheme was selected and subsequently applied in two field wells.Research has shown that the upper and middle sections of the casing predominantly experience CO2 and microbial synergistic corrosion, while the lower section is mainly subject to CO2 corrosion. As the temperature increases, the synergistic effect of CO2 and microorganisms on corrosion diminishes. This results in more severe localized corrosion in the upper section of the casing compare to the middle section. When the temperature reaches the service condition typical for the lower section of the casing, CO2 corrosion accelerates, leading to both localized and uniform corrosion falling within the extremely severe corrosion range. The uniform corrosion resistance of the antibacterial casing deteriorates with increasing temperature, although their resistance to localized corrosion remains good. Chemical anti-corrosion methods can significantly reduce the uniform and localized corrosion of the upper and middle sections of the casing, but high attention should be paid to the adaptability of the chemical under high temperatures. For a 20-year service life, two anti-corrosion schemes suitable for different shale gas blocks have been proposed. The research results can provide technical support for anti-corrosion to ensure the integrity of shale gas wells in the southern Sichuan basin.